What happens to data from Shared iCloud Storage when user leaves?

My family is currently paying for separate iCloud storage plans, and would save quite a few dollars if we move to shared iCloud storage. My question is, if later on my kids leave our Apple family to start their own (they get married, want to separate their accounts, etc...), will they lose the data shared in the storage? There are photos and backups that I'm sure no one would want to lose, but it's not clear if we can safely separate their data if they leave the Apple family.

I did some searching and couldn't find anything to this, and without setting up fake accounts and testing it out, I have no way of knowing. Has anyone done this, or something similar, that could offer advice? I'm sure this situation could come up if kids grow out of an Apple family, or a divorce happens, or similar.

Thanks!