If this feature would be added to the engine, you could layer filters for sounds for specific items. so every time the camera is inside a building, a different Set of filters gets applied to the weapon or explosion sounds so the overall effects sound more dampened, just like when you would be inside a building. then when you're outside the sounds won't be heard as clearly.

The immersion that can be added by this feature would be amazing and help out existing moddres like LordJarHead Creator of the JSRS sound mod and Laxemann creator of Enhanced Soundscape mod.