Exporting buildings with interior

BI0H0G

Got a bit of a dilemma here i working on a project that will have a lot of buildings whit interior like the ones found in battlefield and arma.
My question is do i separate the exterior with the interior or combine them?     

poopipe

It seems sensible to separate them.  You don't want to be drawing the interior unless you can actually see it. 
You'll probably want to break them down into smaller bits though - think about what you'll be able to see at any given frame.. 

BI0H0G

So for example an apartment complex i should be separated in apartments, lobby and stairs and small houses should be separated like this
https://imgur.com/a/BxxQAHX .