Switching beetween UV sets across multiple objects

Toggle UV script

Going by question remit, ie objects having two UV maps, here is a script to toggle between them on selected objects.

Note script for 2.8 see How to change UVMap index? for prior.

import bpy

context = bpy.context

for o in context.selected_objects:
    if o.type != 'MESH':
        continue # only meshes?
    uv = o.data.uv_layers
    ai = uv.active_index
    uv.active_index = 0 if ai else 1
    uv.active.active_render = True

or set absolutely, script below sets all active UV maps to that of index 0.

import bpy

context = bpy.context

for o in context.selected_objects:
    if o.type != 'MESH':
        continue # only meshes?
    uv = o.data.uv_layers
    ai = uv.active_index
    uv.active_index = 0
    uv.active.active_render = True

You could make a "Mix Vector" node and drive the Fac by a common property...

Not sure if this helps...

If it's a case of switching maps, (as opposed to images) The UV Map shader input node looks up by name. The Cube and sphere in the illustrations share a map: 'Shared UV', and each has a map: 'UV Map' of its own.

They share the material, so the switch can be made in the UV Map node.