As far as I can tell, there's no good way to hide a part of your 3D mesh. Even if I have them split into spereate objects, using the paint tool with the oject blocked out stops the paint tool from working. A problem that shows up even on Adobe's personal training video.
All I want is an easy way to hid the mesh from view so that I can't interact with it and see behind it. I feel like there's a lot of tools to do "sort of this" but no way to do exactly this without some big workaround.