Surface Shader's coverage affected by its own displacement in TG3

[Mohawk20]

When trying to make a moss/grass like surface, I want it to stay confined by a slope restriction. But when I give it it a displacement, I want it to have the color of the Shader everywhere on the terrain in front of the Shader that fits the slope restriction.
However, if the displacement is too much, the Shader itself creates a slope that is steeper than the restriction, so the color is not applied. How can I fix that? Child layer or something?

[Dune]

You could try masking the displacement of the moss only to the slopes you need, not the color, and put this all before the rest of the surface shaders, which will then overrule the moss colors, but not the displacement (if you mask them by slope, or whatever).

[Mohawk20]

Oh, you gave me an idea!
Use the current surface shader as a mask for a surface Shader without slope constraint, but with displacement. That might be the easiest solution. Would that work?

[Dune]

Depends on where the surface is in the line (parallel or 'inline'), so you have to check it out.