I am in a similar situation! My 4 babies have been hatching over the last week and at first I put then in a tuppa wear bpx inside the main tank but tonight I have bitten the bullet and put them in with the parents. I just thought how would I feel if my babies were taken away?! I know snails probably dobt have that level of thinking but I do. I think some people keep them together from day one and do fine.
My experience of younguns living in with adults is that they do better in their own space but if they have to live all together, so long as their shell is strong enough to not be crushed easily, they're usually fine.
Sometimes it's problematic if a big one literally sits itself down on the small one and traps it underfoot, and I've found a couple small ones with areas of their shell chewed on where the big ones have suckered onto them and they couldn't move away. No fatalities or bad damage though, make sure the water dish is shallow enough for the smallest snail in there or you may find small ones floating around in the bath!
Snails have no parental instincts. They won't care if their young are moved away and the young won't care either. The fact that they would happily sit on the babies or chew on them is a good illustration of this