Adressbookbased Filter

[florianemrich]

I already wrote about my problem in this thread, but now i think i now how to my problem in theory

Problem: When I want to read a mail, the content should only been shown up, if the sender of the mail is listed in my adressbook. Otherwise there should be shown a message like "Unknown sender. You have to add the sender to your adressbook if you want to read this mail."

Solution: I guess i have to edit the show.inc of /program/steps/mail. I think a if-querry like "if sender is in adressbook, then show content, else show warning message" should fix my problem. But i dont have any idea, where and how to add this code. So if anyone has an idea how to perform the edit, i would be very  very happy