Hi Harry,
Obviously, I don't the know the business process, but I would think you would make union and non-union positions different positions by title i.e. Prep Cook (Union) and Prep Cook (non-union). Looks like you have made Union/Non-Union as attributes, which is fine. Why not configure the drop list either with grouping as you have on the other query, or add a column in the drop list for Union/Non-Union so the user can select accordingly?