Decals and Post-process


I am currently getting into the subject post-process materials and trying to make a camera effect that makes certain objects bright, while masking the rest of them. Similar to the thermal vision, but much simpler (no gradients, no dependency on the distance, etc) I made it work by taking a difference between the CustomDepth and the SceneDepth and setting “Render CustomDepth” flag in the meshes I need.
But now I also would like to highlight certain decals in the same way. Basically, blood spatters that should glow bright, while this special vision effect is active. There’s apparently no CustomDepth flag in the decal rendering parameters, and I didn’t find an easy way around it. So could you help me with this