Using 2 materials with different UVs on the same mesh I am attempting to use two materials on one connected mesh, each with a separate set of UVs. The reason is that I want a high res head, using 4K textures for the head alone and another set of 4K textures for the body.  I have made two UV sets, Head_UV and Body_UV, each has either the head or the body minimized.
I thought I would be able to apply one material to the head polys and one to the body polys and then make each Material use a different UV set by using the UV node in the editor.  I made two materials successfully and the UV nodes seem to feed the right Coordinates to the textures in each.
The problem is that so far I've only been able to get the mesh to either be all one material or the other.  I tried going into edit mode, selecting the polys of either the head or the body and then clicking Apply in the Material panel, but no matter what I do, the mesh is either all head material, or all body material. I'm trying to avoid splitting the mesh, so I don't have to worry about keeping the edge verts together during rigging.
Is it possible to do what I am trying to do? Sorry if I am missing something simple here. I'm pretty well versed in 3D, but relatively new to Blender and I am still figuring out how everything works in it.
Thanks for any advice that might help me.
Figured out what I was doing wrong. Rookie Mistake. I was just switching between the two materials in the materials panel using the popup at the bottom, but always leaving only a single material in the list.
I finally realized I needed to add both of the materials in the list and then assign to the specific polys.  Duh.
Thanks to everyone that looked, and to PGmath for responding.