Buildable Apartments?

I do build "apartments for my sims, and place sims I want to get together and know one another in them. I enjoy starting a sim or small family out this way. The main problem is no privacy as they are always going in each other's apartments. I use it to increase their relationships, but it would be nice to have doors that would work to keep them out, like in Apartments pack Sims 2. I wouldn't want the apartments I am playing to be blacked out or need me switch active sims in the apartment building to play them.