Not sure how to tackle this model


I’m planning on modeling the building I live in, as well as modeling the apartments inside the building for a game I’m working on. I don’t know how to go about this though. Do I model the apartments first, and then surround everything with the building, or do I model the building, and then model the apartments inside? I modeled the apartments, but doing it this way seems to prevent me from being able to place them inside of a building due to each apartment’s different size/layout, and when I attempted to start with the building, I can’t seem to fit twelve apartments on each floor without making the building model a ridiculously large size. Does anyone have any insight as to how I would go about this?