/3/ - 3DCG

I don't even really know how to word this question outside of tiling. I'm a moron, please understand.

I want to put several different textures together on one image. When you only have one texture, you can expand the UV past the texture and it'll automagically tile. This doesn't really work if you have multiple textures in the same image. You can create tiles in the mesh itself and then UV tile as well, but large meshes can end up having way too many tris doing this. Is there a way to tile an entire mesh from a section of a texture?