When using the viewer as a CENTRAL console, multiple operators connect to this viewer with their own logins:
1. The users host list is auto-updated at login. When a new host is added to central console, the viewers are auto-refreshed.
2. User login only allows the user to modify host they are assigned to by site, group, or single host.
We are planning to add a fully-fledged address book sync (and also a web account too) in one of the next releases. As for rights management for address book records - that's also a good idea. We'll see what we can do in this respect.