Post process custom depth on one side of mesh

Can a post process material be used to provide custom depth to one side of a mesh that uses a two sided material. So that one side is one colour and the other side is the other colour. I know this can be done in the material itself but can a post process be used also?

I’m currently trying something like this, although I don’t think TwoSidedSign is the correct node to use. Ignore the subtract and clamp. The reason I want it in post process is so its always in front of fog with the use of custom depth.

For Anyone Interested, here is a workaround. It takes the base colour from the GBuffer and checks if its a certain colour. If it is that colour it will apply it to the emissive of a post process allowing the colour to show through on top of fog.

This has allowed me to have two sided material with only one side getting the custom depth (All Black) and the other side keeping its texture with fog applied, if that makes sense

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Edit: I have made several improvements to this, if interested, I will share those as well.