Option to assign "undiscoverable" privledge to users or groups, essentially preventing other users from locating them while on network.  Example - assigning said privledge to goup 'security personnel', allowing them to roam freely throughout the building while disallowing other users outside 'security personnel' from being able to locate them.  Users in 'sercurity personnel' can locate other users in same group, and when used in congruence with current privledge of locating other users, would be able to locate people outside the group as well.  "Stealth Mode" or "Overwatch" privledges, if you will. 

Inquiry via Greg Harris at Vocera.