We made pallets of blankets on the floor in the same room. For one we made a 'nest" , a bed on the wall over looking our bed. All of them loved this. As each get bigger and go to to the new room the others follow easier. They want to be BIG like their siblings!
When the room felt/ got crowded we would wait till they were asleep to move them to the other bed and/or room.
Each made it to at least 2 and they return when sick. Nothing like hugging your baby, no matter the age!