Hello,
Using the current V-Ray 5 I’ve created my Blend material and duplicated it five times to use different coat mask each time. Coat masks stay connected so no matter what I do, I can even delete the texture in the slot, when I assign a new one, the change applies to all duplicates of the original Blend material.
1. Create 2 bitmap textures, material Blend1 with base and coat material. Set Bitmap1 as coat blend texture (paste as instance).
2. Duplicate Blend1 material and in the new Blend2 material set Bitmap2 as coat blend texture (paste as instance).
3. Voilá! Blend1 material’s coat blend texture has changed too.
This happens to all duplicates of one original blend material, i.e. it cannot be duplicatedand edited afterwards. All individual blend materials have to be created by hand.