Re: Adult siblings living in separate households?

@zgo2fhj1px5m  I would suggest creating the sibling household first, with no spouses or kids, at whatever age you want them, and placing them on one lot in the world.  From there, you could split them (after using cheats to increase their household funds or freerealestate to allow them to purchase other houses) while they maintain their relationships with each other.

You could then take each separate household into CAS and add the other family members.  If you have the current separate households saved to your library, which you probably do, you could import those sims rather than creating them from scratch.