Attach Post Process box on placable objects?

Is it possible to attach (or posses hitbox\invisible mesh) a PostProcess rectangle to specific objects? For example, can I attach it to a foundation, so every time i step on it, I get water effects, or over-exposure, or something like that?

Thank you David!

Can I also add a Physics Volume that becomes ‘non-water cube’ inside a water volume? My plan now is to create foundations and walls that can be placed underwater, and inside these structures there are surface-like conditions (breathing, no swimming, etc.).

Making a water Physical Volume, and placing another default Physical Volume inside it, with higher priority, is manageable. The character walks inside the small box, and swims outside of it, in the bigger one. But how can I achieve this with components? There are no actual PhysicalVolume components, only Constraint and Thruster (which seem different). Also, how would I set this event to stop after leaving the box?