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So looking at this further, it would need for GG to support more UV channels then we can right now. Then even with that it would still need one texture to work.
You will need to mask out your path on the base texture and replace the mask with your rock texture. Mapping that onto your mesh. That will work as you have shown from the above pics.
Made these in Quixel Mixer from your textures.
Brought it into 3ds max and re uv mapped the terrain object.
The results in GG with one texture call in the FPE file.
I will email you the files I have now.
RIP
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