User group manager and queue visibility

[ISDHK]

Hi all,
I would like to know if it is possible to make a user group manager see all the tickets in a particular queue.
My setup is as follows:
Multiple clients with multiple locations;
Each client location is a Dept;
Each Dept. has its own queue;

One user group serves all client locations;
User group manager can see tickets from all locatioins;

All our staff are in registered user group, so that they can create tickets from the feild by email from a PDA.
These tickets are not visible to user group manager now, as it is created by a user from a different group.
What I want to do is to make all tickets in one or more queue/dept. visible to a user group manager.

Any suggestions/Mods/parser rules ?

Many thanks.