[otrs] Use Postmaster to disable call re-opening on followup

Hi All, I'm wondering if there is a way to use Postmaster filter to prevent calls from re-opening after follow up is received. I like the re-opening feature but I would like to disable it for one particular customer. The reason is that when we log calls in otrs, the email from otrs logs a call on the other system. Now when we close the call before they do, their closure notification re-opens our call.. -- Thanks a lot, Robert