I'm trying to find an effective way to deal with multiple decals on a base image texture.
If I keep the decals a separate mesh from the base mesh, I can position and rotate them freely, and add as many as I want, but cannot get the decal to respect the alpha channel of the base. If instead I add the decal as a set of nodes in the base material, the color of the decal is clipped in the way I want, but adding more seems like a huge amount of work connecting nodes, and doesn't give me the luxury of moving the decals around in the scene as I see fit, and makes it difficult to reuse the results without copying and pasting nodes onto every material in the scene. If I wanted to add, say, 30 decals to a mesh, there's no way I'd be able to keep track of them all in the node editor and wire them up correctly.
Is there some way I can get the best of both worlds? Proper alpha clipping and the flexibility of working with individual meshes instead of a tree with a geometrically increasing number of nodes?
See the screenshots below. I'll try and figure out how to upload these as well if that helps.
Here's the nodes version: 
And the mesh version: 
