World Adventures. Your sims can live there with the right visa. There is also an NRAS mod called Traveller or it could be Mover or both that allows you to live in other worlds like University.
You can have children at the World Adventures but not at University. I don't know about aging either. That's without mods.
What puzzlezaddict said too, Edit Town. It never occurred to me about it having an address though. I don't know if that would matter, does it affect anything technical?
Try a water property, like a houseboat, or a waterfront property. With the Town Edit tool. There should be a few vacant lots already. If you haven't used up some of the spare community lots and don't plan to, you could change the zone/lot type of those to residential as well. And demolish one or two community lots that you never use, and change the lot type of those, and one or two residentials you don't like. Or many. Surely, they will add up to enough.
I had a family who had too many babies and so when they grew up there was no room for them all to have a second or third generation and I didn't want to not control them, flapping in the wind out in the neighbourhood all on their own. So I made a copy of the game/world/family, moved half of them to a new world where they took the gravestones and urns of everyone they could with them, to preserve those relations, and the other half moved to another world with the gravestones too and their other corresponding dead relatives too, by marriage. So then I had 3 or was it 4, copies of them. 2 still in Sunset Valley not being played anymore, and 1 each in the new worlds being played as branches, and in my imagination and the story they talk about each other as though they heard the gossip or spoke on the phone. If you don't take the gravestones including the one's in between, they don't turn up in the family tree. That was the Plunkett family on my My Sims page, and turned out to be a pretty good story.
A few suggestions there.
