By-pass for excluding deferred decal from Post Processing Volume

From what I’m reading online it’s currently not possible to use a custom depth stencil for deferred decals, because they don’t have any depth. It’s apparently also not possible to pass in a custom tags or custom values that can be checked for in the shader material to exclude, because deferred decals will blend with the underlying material, therefore we cannot check for any sort of unused base colour or specular to exclude.

I’m pretty sure GBuffer was also not reliable because it will still check for the blended colour as opposed to the base colour (right?)

I’m wondering if there is any sort of by-pass to exclude a specific deferred decal from a Post Processing volume. It seems like such a trivial thing, yet it’s giving me a difficult time right now.

Surely there is a way.

You could perhaps spawn a proxy object that is only drawn in the custom depth pass in the same spot as the decal. Then when you exclude that proxy from postprocessing, it will naturally exclude the decal as well.