Directional light with no shadow makes indoor bright too!

Hello guys. I need to do something please help me if that is possible!
I need to use a directional light without any shadow but I have a problem that it makes indoor places bright too. Because this directional light doesn’t have any shadow.
Is there anyway to use a directional light with no shadow but still make this light to bright outdoor area only?

Use layers, and set the light to only affect the appropriate layer.

–Eric