You can add a sun occlusion factor to your scene's materials, if your material is used outdoor you set this factor so it doesn't occlude sunlight, if it's used indoor you set it so it does occlude sunlight.
If you're using a deferred renderer you can store this value in your GBuffer.

I believe this technique is quite commonly used in some major engines and it's quite simple to implement.

If you implement shadows, you can also just rely on the shadows to deal with shadowing light sources located outside the house. Although what with shadows being a bit of a black art (no pun intended), you may need to fudge things a little.

I think that if the house is really it's own environment, then you need to control it directly in order to get proper lighting. On the other hand, if it is like 007 on the N64 where you walk into the shacks but it isn't very "important" than it doesn't make much difference. I'm not sure how you are rendering these graphics. If you are using OpenGL directly, you can change lighting scheme between rendering different objects so that the house has its own lighting. The catch is that you'd have to create models for the outside and for the inside, although if you already have a single model that has polys on both sides, you may be able to just split them in your modeling software.