[otrs] Problem in creating event notification

Hi,

Currently our OTRS setup is generating tickets based on incoming emails. We want to add a notification to a particular email id e.g. group@abc.com in case email contains a particular text e.g. "device: abc".

To solve this, we configured a postmaster filter to read the email body and set X-OTRS-header 'X-OTRS-CustomerNo' to 'abc'. Now, I want to create a event notification for new tickets and use this X-OTRS-header in ticket filters but don't see any option like that. Is this the right approach? If yes, how to create a event notification on 'X-OTRS-CustomerNo'? Regards, Saurabh