I’m not sure what you’re looking for here. A UV set is a named set of coordinates that are applied to vertices. You want to look at a set of polygons and figure out what UV sets are applied to it? Or you want to figure out which set of polygons in a model have a given UV set applied?
Both of these are possible by iterating through the low-level geometry and examining the actual vertex data, but there’s not a high-level function to do it for you. Still, it’s a weird thing to do. Don’t you know what UV sets you have already applied to your geometry before you start? Just structure your model so that all of the pieces that have a particular UV set are grouped under a common node, and then you won’t have to do any hunting and searching at runtime.
David