This map that tracks the movements of six wolf packs in a park* shows how well they can distinguish between the members of their own pack and other packs. They may see or hear each other at times but I think there’s no question that scent is the primary way they maintain these borders.
It still doesn’t tell us if they can tell one member or their own pack from another purely on the scent of their urine. It seems possible that whatever allows dogs to distinguish us by scent otherwise could be present in our urine even if it only is there in just trace amounts.
*Map linked to from this thread: ? Awesome Maps