Rendering all objects in a volume.

I’m currently working on a side-scrolling project where the player can move through the world via elements in the foreground and background, and have the camera set up in such a way that they can see into open doors in the background, creating a nice feeling of cohesion.

Unfortunately, with the nature of the orthographic camera; Assets in the previous ‘layer’ interrupt the player’s perspective - Is there anyway to set a volume for, say, a hallway, that will cease all rendering of everything inside of it once the player leaves?
Ideally, I’d like to make it so only the hallways/rooms the player is in are visible, stripping the front facing wall so that the player can see their character.

Here is my experimental setup, you can see the background door for the player to enter, and the ‘main’ hall I’d like to obscure entirely.

Any feedback or suggestions would be greatly appreciated!