not sure I'd put the 2 youngest together. I'd think more chance of them waking eachother up. At least, if a baby wakes an older kid you can explain to them to ignore baby and they still have to lie quietly...hopefully resulting in them falling back to sleep. I also wouldn't necessarily put the siblings together, unless they're the best sleepers. I put my best sleeper or oldest with baby. And usually put baby down a few minutes before so they're already asleep when their partner arrives, so no fooling around or keeping eachother up. And if it's 2 babies, well each in a different room put down slightly before the others, then 2 best sleeper each get a baby and sneak in quietly....