Window > Relationship Editors > UV Linking , then just pick either texture centric or UV centric. So, for instance if you have a blinn with a diffuse, and transparency texture, you can link the diffuse to one UV set, and the transparency to another.
what do you mean? Do you want to have some sort of detail map or lightmap with its own uvs that adds on top of a regular shading? Or do you want maybe having a regular shading with regular uvs; and having some sort of mask that will display another shading -like a pattern maybe - that has its own uvs? Or maybe you simply…