Pod,

You on the right path. In the parlance of .obj files, groups and materials generally make sense only as facets (faces) in Poser. (.obj is not a very modern format.) When you make a selection in UV Mapper, it will only show that selection and hide the rest. Just use "Select All" (ctrl-A) to make the whole model re-appear.

Since you are using multiple UV maps on the same model (which is common with poser figures) you will definitely want to also create selections of the pieces that belong to each UV map and assign a unique material to each. This will allow you to apply the separate UV maps later in Poser's material room.

-K