We know how to do either 1. + 3. or 1. + 2. But we cannot figure out how to achieve all three goals at the same time. Any hints?

Hi Moritz, We solved this by creating a dummy mail-address that forwards all mail to /dev/null. All phone tickets are from 'Name ', and thus no mail is being sent to the customers. I know this is the easy way out, but it works for us :-) -Thomas