@Zasz currently in City Living it is only loading the neighboring households when they do activities in the common space, such as taking out the trash or checking the mail. Multi household lots could work the same way. You have to go to manage worlds and then select a different house on the lot in order to play with a different family. If you wanted your sim to actually go in another sim's house, it would have to load that separately. You could also catch your neighbors walking in the common space and visit with them there without loading. It would be pretty awesome to have it all loaded at once, but I don't think that would work on the average simmer's computer.
