Enable ticket watch functionality for certain groups

[aph]

I would like to enable the ticket watcher functionality for the group admin. Hence, I made the following settings in Ticket -> Core::TicketWatcher
Ticket::Watcher = Yes
Ticket::WatcherGroup = admin

As a result only memebers of the group admin see the 'watch' button in ticket zoom view.

However, on the dashboard all agents have a new link 'my watched tickets' next to locked tickets, my responsibilities and so on.

How do I disable this for groups that do not have permissions to watch tickets in the first place?