[otrs] Help with X-OTRS

I have a few users that like to shout at the world and do so by sending a 'CC' to multiple people including my helpdesk address (even thought the message is not for the helpdesk). I would like to setup an X-OTRS filter that ignores mail if it comes to the helpdesk via 'CC'. I have tried: [...] Match => { CC => 'email@example.com', #place my actual helpdesk address here }, Set => { 'X-OTRS-Ignore' => 'yes', } [...] But the email still comes through. Have I not set this up properly? Or is it not possible to do this?