How to blend displacement maps based on slope masks?

I am trying to apply tessellation to my auto terrain material which blends layers based on slope angle combined with their heightmaps to create less uniform edges of the transitions. That all works fine but I can’t get displacement based on slope angles to work! I can either get 1 displacement to work across the whole terrain and I get weird issues.

Is it not possible to layerblend displacement maps? because that is what I am starting to think… :confused: