Projection on Multiple Surfaces + alpha

I need a way to use “1.4 - Projection on Multiple Surfaces” but avoiding the projection over the surface alpha.

A way between “1.4 - Projection on Multiple Surfaces” and “1.5 Receives Decals Off”

https://docs.unrealengine.com/latest/images/Resources/ContentExamples/Decals/Decals_5.jpg

¿Is there a way?

Wait, so you want a mask within a material that says ‘i can recieve decals’?.. im not sure that is possible.

Yes, part of the surface mesh receives the decal, the other part nothing (the alpha mask part).
The aim is to use it as blend between meshes and landscape. I tried a lot of diferent methods, all with problems:
-vertex painting blend.
-depth_fade blend
-pixel_depth_fade blend
-layers blend

This image is from vertex paint , but is a tedious work for big scenes.
My idea is to map a big image over meshes.

Not possible without engine code changes.

Thanks for clarify Ryan.
I will try another way.