Exterior lighting lit up but interior lighting in same scene not lit up? How to do that?

I want to have a scene where the outside environment is daylight and then there is a building in the area that if the player goes into the basement of it gets dark and they have to use a flashlight? Does anyone know how to do that? Because the directional light lights up everything, so even a cube on the inside is still lit. So how can I create surfaces that block light?

Set a trigger in the building. When the player enters, disable the directional light. When they exit, reactivate it.