Search for tickets which users *@xyz.com have been the last to post messasges in

I’m looking for a methode inside the gui of RT to
search for all tickets which users of a particular company / wich a pattern in Email-adress
(e.g. @xyz.com) have been the last to post a messasges into.

I am a admin via rt’s gui, not a programmer nor able to do much configuration work at the linux console.

So far, I’ve tried to find some fields to put such search together but did not find anything helping.

I’m using RT 4.2.10 on RHEL.

Can anyone point me in the right direction?

regards,
Thomas Schubert