diff --git a/cmd/solver-tune/main.go b/cmd/solver-tune/main.go
index f679621..ac97c02 100644
--- a/cmd/solver-tune/main.go
+++ b/cmd/solver-tune/main.go
@@ -15,10 +15,15 @@ import (
 	"rooms/solver"
 )
 
+type roomGroupData struct {
+	Size  int `json:"size"`
+	Count int `json:"count"`
+}
+
 type tripData struct {
-	RoomSize          int `json:"room_size"`
-	PreferNotMultiple int `json:"prefer_not_multiple"`
-	NoPreferCost      int `json:"no_prefer_cost"`
+	PreferNotMultiple int             `json:"prefer_not_multiple"`
+	NoPreferCost      int             `json:"no_prefer_cost"`
+	RoomGroups        []roomGroupData `json:"room_groups"`
 }
 
 type studentData struct {
@@ -189,7 +194,18 @@ func main() {
 		})
 	}
 
-	fmt.Printf("Students: %d, Room size: %d, Constraints: %d\n", n, trip.RoomSize, len(constraints))
+	var roomSizes []int
+	for _, rg := range trip.RoomGroups {
+		for range rg.Count {
+			roomSizes = append(roomSizes, rg.Size)
+		}
+	}
+	if len(roomSizes) == 0 {
+		fmt.Fprintf(os.Stderr, "no room_groups in trip data\n")
+		os.Exit(1)
+	}
+
+	fmt.Printf("Students: %d, Room sizes: %v, Constraints: %d\n", n, roomSizes, len(constraints))
 	fmt.Printf("Prefer Not multiple: %d, No Prefer cost: %d\n", trip.PreferNotMultiple, trip.NoPreferCost)
 	fmt.Printf("Runs per config: %d\n\n", *runs)
 
@@ -207,7 +223,7 @@ func main() {
 			for run := range *runs {
 				rng := rand.New(rand.NewSource(int64(run * 31337)))
 				start := time.Now()
-				sols := solver.SolveFast(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
+				sols := solver.SolveFast(n, roomSizes, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
 				elapsed := time.Since(start)
 				if len(sols) > 0 {
 					var assignments [][]int
diff --git a/drop.sql b/drop.sql
index 07edf98..058282e 100644
--- a/drop.sql
+++ b/drop.sql
@@ -1,6 +1,7 @@
 DROP TABLE IF EXISTS roommate_constraints;
 DROP TABLE IF EXISTS parents;
 DROP TABLE IF EXISTS students;
+DROP TABLE IF EXISTS room_groups;
 DROP TABLE IF EXISTS trip_admins;
 DROP TABLE IF EXISTS trips;
 DROP TYPE IF EXISTS constraint_level;
diff --git a/main.go b/main.go
index e536008..b532459 100644
--- a/main.go
+++ b/main.go
@@ -87,6 +87,9 @@ func main() {
 	http.HandleFunc("GET /api/trips/{tripID}/constraints", handleListConstraints(db))
 	http.HandleFunc("POST /api/trips/{tripID}/constraints", handleCreateConstraint(db))
 	http.HandleFunc("DELETE /api/trips/{tripID}/constraints/{constraintID}", handleDeleteConstraint(db))
+	http.HandleFunc("GET /api/trips/{tripID}/room-groups", handleListRoomGroups(db))
+	http.HandleFunc("POST /api/trips/{tripID}/room-groups", handleCreateRoomGroup(db))
+	http.HandleFunc("DELETE /api/trips/{tripID}/room-groups/{groupID}", handleDeleteRoomGroup(db))
 	http.HandleFunc("POST /api/trips/{tripID}/solve", handleSolve(db))
 	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
 		if err := db.Ping(); err != nil {
@@ -295,13 +298,13 @@ func handleListTrips(db *sql.DB) http.HandlerFunc {
 			return
 		}
 		rows, err := db.Query(`
-			SELECT t.id, t.name, t.room_size, t.prefer_not_multiple, t.no_prefer_cost, COALESCE(
+			SELECT t.id, t.name, t.prefer_not_multiple, t.no_prefer_cost, COALESCE(
 				json_agg(json_build_object('id', ta.id, 'email', ta.email)) FILTER (WHERE ta.id IS NOT NULL),
 				'[]'
 			)
 			FROM trips t
 			LEFT JOIN trip_admins ta ON ta.trip_id = t.id
-			GROUP BY t.id, t.name, t.room_size, t.prefer_not_multiple, t.no_prefer_cost
+			GROUP BY t.id, t.name, t.prefer_not_multiple, t.no_prefer_cost
 			ORDER BY t.id`)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -316,7 +319,6 @@ func handleListTrips(db *sql.DB) http.HandlerFunc {
 		type trip struct {
 			ID                 int64       `json:"id"`
 			Name               string      `json:"name"`
-			RoomSize           int         `json:"room_size"`
 			PreferNotMultiple  int         `json:"prefer_not_multiple"`
 			NoPreferCost       int         `json:"no_prefer_cost"`
 			Admins             []tripAdmin `json:"admins"`
@@ -326,7 +328,7 @@ func handleListTrips(db *sql.DB) http.HandlerFunc {
 		for rows.Next() {
 			var t trip
 			var adminsJSON string
-			if err := rows.Scan(&t.ID, &t.Name, &t.RoomSize, &t.PreferNotMultiple, &t.NoPreferCost, &adminsJSON); err != nil {
+			if err := rows.Scan(&t.ID, &t.Name, &t.PreferNotMultiple, &t.NoPreferCost, &adminsJSON); err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)
 				return
 			}
@@ -470,14 +472,14 @@ func handleGetTrip(db *sql.DB) http.HandlerFunc {
 			return
 		}
 		var name string
-		var roomSize, preferNotMultiple, noPreferCost int
-		err := db.QueryRow("SELECT name, room_size, prefer_not_multiple, no_prefer_cost FROM trips WHERE id = $1", tripID).Scan(&name, &roomSize, &preferNotMultiple, &noPreferCost)
+		var preferNotMultiple, noPreferCost int
+		err := db.QueryRow("SELECT name, prefer_not_multiple, no_prefer_cost FROM trips WHERE id = $1", tripID).Scan(&name, &preferNotMultiple, &noPreferCost)
 		if err != nil {
 			http.Error(w, "trip not found", http.StatusNotFound)
 			return
 		}
 		w.Header().Set("Content-Type", "application/json")
-		json.NewEncoder(w).Encode(map[string]any{"id": tripID, "name": name, "room_size": roomSize, "prefer_not_multiple": preferNotMultiple, "no_prefer_cost": noPreferCost})
+		json.NewEncoder(w).Encode(map[string]any{"id": tripID, "name": name, "prefer_not_multiple": preferNotMultiple, "no_prefer_cost": noPreferCost})
 	}
 }
 
@@ -672,7 +674,6 @@ func handleUpdateTrip(db *sql.DB) http.HandlerFunc {
 			return
 		}
 		var body struct {
-			RoomSize          *int `json:"room_size"`
 			PreferNotMultiple *int `json:"prefer_not_multiple"`
 			NoPreferCost      *int `json:"no_prefer_cost"`
 		}
@@ -680,12 +681,6 @@ func handleUpdateTrip(db *sql.DB) http.HandlerFunc {
 			http.Error(w, "invalid request body", http.StatusBadRequest)
 			return
 		}
-		if body.RoomSize != nil {
-			if *body.RoomSize < 1 {
-				http.Error(w, "room_size must be at least 1", http.StatusBadRequest)
-				return
-			}
-		}
 		if body.PreferNotMultiple != nil {
 			if *body.PreferNotMultiple < 1 {
 				http.Error(w, "prefer_not_multiple must be at least 1", http.StatusBadRequest)
@@ -698,12 +693,6 @@ func handleUpdateTrip(db *sql.DB) http.HandlerFunc {
 				return
 			}
 		}
-		if body.RoomSize != nil {
-			if _, err := db.Exec("UPDATE trips SET room_size = $1 WHERE id = $2", *body.RoomSize, tripID); err != nil {
-				http.Error(w, err.Error(), http.StatusInternalServerError)
-				return
-			}
-		}
 		if body.PreferNotMultiple != nil {
 			if _, err := db.Exec("UPDATE trips SET prefer_not_multiple = $1 WHERE id = $2", *body.PreferNotMultiple, tripID); err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -993,16 +982,18 @@ func handleListConstraints(db *sql.DB) http.HandlerFunc {
 				hardConflicts = append(hardConflicts, chain)
 			}
 
-			var roomSize int
-			db.QueryRow("SELECT room_size FROM trips WHERE id = $1", tripID).Scan(&roomSize)
+			var maxRoomSize int
+			db.QueryRow("SELECT COALESCE(MAX(size), 0) FROM room_groups WHERE trip_id = $1", tripID).Scan(&maxRoomSize)
 			mustGroups := map[int64][]string{}
 			for _, id := range studentIDs {
 				root := ufFind(id)
 				mustGroups[root] = append(mustGroups[root], studentName[id])
 			}
-			for _, members := range mustGroups {
-				if len(members) > roomSize {
-					oversizedGroups = append(oversizedGroups, members)
+			if maxRoomSize > 0 {
+				for _, members := range mustGroups {
+					if len(members) > maxRoomSize {
+						oversizedGroups = append(oversizedGroups, members)
+					}
 				}
 			}
 		}
@@ -1119,6 +1110,93 @@ func handleDeleteConstraint(db *sql.DB) http.HandlerFunc {
 	}
 }
 
+func handleListRoomGroups(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		_, tripID, ok := requireTripAdmin(db, w, r)
+		if !ok {
+			return
+		}
+		rows, err := db.Query("SELECT id, size, count FROM room_groups WHERE trip_id = $1 ORDER BY id", tripID)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		defer rows.Close()
+		type roomGroup struct {
+			ID    int64 `json:"id"`
+			Size  int   `json:"size"`
+			Count int   `json:"count"`
+		}
+		var groups []roomGroup
+		for rows.Next() {
+			var g roomGroup
+			if err := rows.Scan(&g.ID, &g.Size, &g.Count); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			groups = append(groups, g)
+		}
+		if groups == nil {
+			groups = []roomGroup{}
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(groups)
+	}
+}
+
+func handleCreateRoomGroup(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		_, tripID, ok := requireTripAdmin(db, w, r)
+		if !ok {
+			return
+		}
+		var body struct {
+			Size  int `json:"size"`
+			Count int `json:"count"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+			http.Error(w, "invalid request body", http.StatusBadRequest)
+			return
+		}
+		if body.Size < 1 || body.Count < 1 {
+			http.Error(w, "size and count must be at least 1", http.StatusBadRequest)
+			return
+		}
+		var id int64
+		err := db.QueryRow("INSERT INTO room_groups (trip_id, size, count) VALUES ($1, $2, $3) RETURNING id", tripID, body.Size, body.Count).Scan(&id)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{"id": id, "size": body.Size, "count": body.Count})
+	}
+}
+
+func handleDeleteRoomGroup(db *sql.DB) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		_, tripID, ok := requireTripAdmin(db, w, r)
+		if !ok {
+			return
+		}
+		groupID, err := strconv.ParseInt(r.PathValue("groupID"), 10, 64)
+		if err != nil {
+			http.Error(w, "invalid group ID", http.StatusBadRequest)
+			return
+		}
+		result, err := db.Exec("DELETE FROM room_groups WHERE id = $1 AND trip_id = $2", groupID, tripID)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		if n, _ := result.RowsAffected(); n == 0 {
+			http.Error(w, "room group not found", http.StatusNotFound)
+			return
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}
+}
+
 func handleSolve(db *sql.DB) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		_, tripID, ok := requireTripAdmin(db, w, r)
@@ -1126,13 +1204,35 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 			return
 		}
 
-		var roomSize, pnMultiple, npCost int
-		err := db.QueryRow("SELECT room_size, prefer_not_multiple, no_prefer_cost FROM trips WHERE id = $1", tripID).Scan(&roomSize, &pnMultiple, &npCost)
+		var pnMultiple, npCost int
+		err := db.QueryRow("SELECT prefer_not_multiple, no_prefer_cost FROM trips WHERE id = $1", tripID).Scan(&pnMultiple, &npCost)
 		if err != nil {
 			http.Error(w, "trip not found", http.StatusNotFound)
 			return
 		}
 
+		rgRows, err := db.Query("SELECT size, count FROM room_groups WHERE trip_id = $1 ORDER BY id", tripID)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		defer rgRows.Close()
+		var roomSizes []int
+		for rgRows.Next() {
+			var size, count int
+			if err := rgRows.Scan(&size, &count); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			for range count {
+				roomSizes = append(roomSizes, size)
+			}
+		}
+		if len(roomSizes) == 0 {
+			http.Error(w, "no room groups configured", http.StatusBadRequest)
+			return
+		}
+
 		rows, err := db.Query("SELECT id, name FROM students WHERE trip_id = $1 ORDER BY id", tripID)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -1219,14 +1319,14 @@ func handleSolve(db *sql.DB) http.HandlerFunc {
 		}
 
 		rng := rand.New(rand.NewSource(42))
-		solutions := solver.SolveFast(n, roomSize, pnMultiple, npCost, constraints, solver.DefaultParams, rng)
+		solutions := solver.SolveFast(n, roomSizes, pnMultiple, npCost, constraints, solver.DefaultParams, rng)
 
 		if solutions == nil {
 			http.Error(w, "hard conflicts exist, resolve before solving", http.StatusBadRequest)
 			return
 		}
 
-		numRooms := (n + roomSize - 1) / roomSize
+		numRooms := len(roomSizes)
 
 		type roomMember struct {
 			ID   int64  `json:"id"`
diff --git a/schema.sql b/schema.sql
index 586009b..471792d 100644
--- a/schema.sql
+++ b/schema.sql
@@ -11,11 +11,19 @@ END $$;
 CREATE TABLE IF NOT EXISTS trips (
     id BIGSERIAL PRIMARY KEY,
     name TEXT NOT NULL,
-    room_size INTEGER NOT NULL DEFAULT 2,
     prefer_not_multiple INTEGER NOT NULL DEFAULT 5,
     no_prefer_cost INTEGER NOT NULL DEFAULT 10
 );
 
+CREATE TABLE IF NOT EXISTS room_groups (
+    id BIGSERIAL PRIMARY KEY,
+    trip_id BIGINT NOT NULL REFERENCES trips(id) ON DELETE CASCADE,
+    size INTEGER NOT NULL,
+    count INTEGER NOT NULL,
+    CHECK(size >= 1),
+    CHECK(count >= 1)
+);
+
 CREATE TABLE IF NOT EXISTS trip_admins (
     id BIGSERIAL PRIMARY KEY,
     trip_id BIGINT NOT NULL REFERENCES trips(id) ON DELETE CASCADE,
diff --git a/solver/solver.go b/solver/solver.go
index 97be1b8..b372ec3 100644
--- a/solver/solver.go
+++ b/solver/solver.go
@@ -57,9 +57,9 @@ func normalizeKey(a []int) string {
 }
 
 type solverState struct {
-	n          int
-	roomSize   int
-	numRooms   int
+	n         int
+	roomSizes []int
+	numRooms  int
 	pnMultiple int
 	npCost     int
 
@@ -77,11 +77,11 @@ type solverState struct {
 	mustApartFor       [][]int
 }
 
-func newSolverState(n, roomSize, pnMultiple, npCost int, constraints []Constraint) *solverState {
+func newSolverState(n int, roomSizes []int, pnMultiple, npCost int, constraints []Constraint) *solverState {
 	s := &solverState{
 		n:          n,
-		roomSize:   roomSize,
-		numRooms:   (n + roomSize - 1) / roomSize,
+		roomSizes:  roomSizes,
+		numRooms:   len(roomSizes),
 		pnMultiple: pnMultiple,
 		npCost:     npCost,
 		constraints: constraints,
@@ -235,7 +235,6 @@ func (s *solverState) feasibleForGroup(assignment []int, groupRoot int, room int
 
 func (s *solverState) fastHillClimb(assignment []int) int {
 	n := s.n
-	roomSize := s.roomSize
 	numRooms := s.numRooms
 
 	roomCounts := make([]int, numRooms)
@@ -386,7 +385,7 @@ func (s *solverState) fastHillClimb(assignment []int) int {
 				if room == gRoom {
 					continue
 				}
-				if roomCounts[room]+len(grp) > roomSize {
+				if roomCounts[room]+len(grp) > s.roomSizes[room] {
 					continue
 				}
 				if !s.feasibleForGroup(assignment, gRoot, room) {
@@ -410,7 +409,7 @@ func (s *solverState) fastHillClimb(assignment []int) int {
 				}
 				newGRoom := roomCounts[gRoom] - len(grp) + len(grp2)
 				newG2Room := roomCounts[g2Room] - len(grp2) + len(grp)
-				if newGRoom > roomSize || newG2Room > roomSize {
+				if newGRoom > s.roomSizes[gRoom] || newG2Room > s.roomSizes[g2Room] {
 					continue
 				}
 				if !s.feasibleForGroup(assignment, gRoot, g2Room) {
@@ -456,9 +455,7 @@ func (s *solverState) fastHillClimb(assignment []int) int {
 
 func (s *solverState) initialPlacement(assignment []int) bool {
 	roomCap := make([]int, s.numRooms)
-	for i := range roomCap {
-		roomCap[i] = s.roomSize
-	}
+	copy(roomCap, s.roomSizes)
 
 	var placeGroups func(gi int) bool
 	placeGroups = func(gi int) bool {
@@ -517,9 +514,7 @@ func (s *solverState) initialPlacement(assignment []int) bool {
 
 func (s *solverState) randomPlacement(assignment []int, rng *rand.Rand) bool {
 	roomCap := make([]int, s.numRooms)
-	for i := range roomCap {
-		roomCap[i] = s.roomSize
-	}
+	copy(roomCap, s.roomSizes)
 	perm := rng.Perm(len(s.groupList))
 	for _, pi := range perm {
 		grp := s.groupList[pi]
@@ -597,12 +592,12 @@ func (t *solutionTracker) add(a []int, s int) {
 	}
 }
 
-func SolveFast(n, roomSize, pnMultiple, npCost int, constraints []Constraint, params Params, rng *rand.Rand) []Solution {
+func SolveFast(n int, roomSizes []int, pnMultiple, npCost int, constraints []Constraint, params Params, rng *rand.Rand) []Solution {
 	if n == 0 {
 		return nil
 	}
 
-	st := newSolverState(n, roomSize, pnMultiple, npCost, constraints)
+	st := newSolverState(n, roomSizes, pnMultiple, npCost, constraints)
 	if st.hasHardConflict() {
 		return nil
 	}
@@ -637,8 +632,8 @@ func SolveFast(n, roomSize, pnMultiple, npCost int, constraints []Constraint, pa
 		for _, room := range a {
 			rc[room]++
 		}
-		for _, cnt := range rc {
-			if cnt > roomSize {
+		for room, cnt := range rc {
+			if cnt > st.roomSizes[room] {
 				return false
 			}
 		}
@@ -657,7 +652,7 @@ func SolveFast(n, roomSize, pnMultiple, npCost int, constraints []Constraint, pa
 				if room == oldRoom {
 					continue
 				}
-				if roomCount(assignment, room)+len(grp) > roomSize {
+				if roomCount(assignment, room)+len(grp) > st.roomSizes[room] {
 					continue
 				}
 				for _, m := range grp {
diff --git a/static/trip.html b/static/trip.html
index 318e354..45e393b 100644
--- a/static/trip.html
+++ b/static/trip.html
@@ -95,7 +95,15 @@
         <h2 id="trip-name"></h2>
         <div id="admin-view" style="display: none;">
             <div id="trip-settings">
-                <label>Students per room: <input id="room-size" type="number" min="1"></label>
+                <div id="room-groups">
+                    <div class="tags" id="room-group-tags"></div>
+                    <div style="display: flex; gap: 0.3rem; align-items: center; flex-wrap: wrap;">
+                        <wa-input id="new-rg-count" type="number" min="1" placeholder="Count" size="small" style="width: 5rem;"></wa-input>
+                        <span>rooms of</span>
+                        <wa-input id="new-rg-size" type="number" min="1" placeholder="Size" size="small" style="width: 5rem;"></wa-input>
+                        <wa-button id="add-rg-btn" size="small">Add</wa-button>
+                    </div>
+                </div>
                 <label>Prefer Not cost: <input id="pn-multiple" type="number" min="1"></label>
                 <label>No Prefer cost: <input id="np-cost" type="number" min="0"></label>
             </div>
diff --git a/static/trip.js b/static/trip.js
index 5ce9d54..44bb7f4 100644
--- a/static/trip.js
+++ b/static/trip.js
@@ -30,13 +30,41 @@ if (me.role !== 'admin') {
 await (async () => {
 
 document.getElementById('admin-view').style.display = 'block';
-document.getElementById('room-size').value = trip.room_size;
 document.getElementById('pn-multiple').value = trip.prefer_not_multiple;
 document.getElementById('np-cost').value = trip.no_prefer_cost;
-document.getElementById('room-size').addEventListener('change', async () => {
-    const size = parseInt(document.getElementById('room-size').value);
-    if (size >= 1) await api('PATCH', '/api/trips/' + tripID, { room_size: size });
+
+let roomGroups = [];
+
+async function loadRoomGroups() {
+    roomGroups = await api('GET', '/api/trips/' + tripID + '/room-groups');
+    const tags = document.getElementById('room-group-tags');
+    tags.innerHTML = '';
+    for (const rg of roomGroups) {
+        const tag = document.createElement('wa-tag');
+        tag.size = 'small';
+        tag.setAttribute('with-remove', '');
+        tag.textContent = rg.count + ' \u00d7 ' + rg.size + '-person';
+        tag.addEventListener('wa-remove', async () => {
+            await api('DELETE', '/api/trips/' + tripID + '/room-groups/' + rg.id);
+            loadRoomGroups();
+        });
+        tags.appendChild(tag);
+    }
+}
+await loadRoomGroups();
+
+document.getElementById('add-rg-btn').addEventListener('click', async () => {
+    const sizeInput = document.getElementById('new-rg-size');
+    const countInput = document.getElementById('new-rg-count');
+    const size = parseInt((sizeInput.value || '').trim());
+    const count = parseInt((countInput.value || '').trim());
+    if (!size || size < 1 || !count || count < 1) return;
+    await api('POST', '/api/trips/' + tripID + '/room-groups', { size, count });
+    sizeInput.value = '';
+    countInput.value = '';
+    loadRoomGroups();
 });
+
 document.getElementById('pn-multiple').addEventListener('change', async () => {
     const val = parseInt(document.getElementById('pn-multiple').value);
     if (val >= 1) await api('PATCH', '/api/trips/' + tripID, { prefer_not_multiple: val });
@@ -158,7 +186,8 @@ async function loadStudents() {
             const div = document.createElement('div');
             div.className = 'conflict-row';
             div.appendChild(kindSpan('must'));
-            div.appendChild(document.createTextNode(' group too large (' + members.length + ' for room size ' + trip.room_size + '): ' + members.join(', ')));
+            const maxSize = roomGroups.length > 0 ? Math.max(...roomGroups.map(g => g.size)) : 0;
+            div.appendChild(document.createTextNode(' group too large (' + members.length + ' for max room size ' + maxSize + '): ' + members.join(', ')));
             det.appendChild(div);
         }
         hardConflictsEl.appendChild(det);