Camera mask by scene

I was wondering if there's a way to make a camera render only the objects in a specific additive scene, without doing hacky stuff like turning all objects off in scene 1, then render scene 2, or putting all objects in a scene into a specific layer (that would break what I am creating, and doesn't seem flexible).

I can't seem to find anything about this (And there might not be). I had really hoped I could find a neat way to do this without creating my own Camera module again.

Anything, any lead, is helpful.

Please and thank you.