For my PC game, I wanted one family to have more than one teen, so I moved out their other teens, and edited more teens into the family. The moved out teens are neighbors to each other in the same area, and still visit their parents and siblings.
Further plans for my PC and PS4 Sim teens is to keep them with their families until they are young adults, unless I have teens I want to marry later on. I have two teens I moved out to live with a young adult Sim, and I am building up their relationship, so I can marry them as young adults and marry them to each other.
With some other teens, and young adults, I will let them explore the world(s), and move the heirs back into their childhood home, and let non-heirs live elsewhere.
Heir teens/young adults will "inherit" their childhood homes, and will have the most kids, while the other teens/young adults where they are more free to move around and explore, with kids being an option for them.