What's the difference between a profile admin, a master admin and a power user?
Using Jamroom
Deb - Checkout the latest AutoFollow module - https://www.jamroom.net/the-jamroom-network/networkmarket/287/auto-follow
If you configure it so that your 'Host' profiles are automatically followed by new users, they can get a notification email about that so they will know about new users without being Profile Admins.
hth