QuoteEach window is separate and has it's own shader
So it is within one object? I'm thinking without TG at hand now, so I might have it wrong; if you make a surface shader, just anywhere, no color, add the glass setup as child, and name the surface shader something simple (A GLASS). Then go inside the object(s), add a null shader, connect its input (rightclick) to the A GLASS, and its output into the object's parts shader (delete the default shader that was attached to it). From my head, that should work.