With help from Carsten I finally hacked a script, that solved an old Problem with my particular setup of Exim and Cyrus.

If you're not administrating these two packages, simply ignore this entry. If you do, take a look: it'll save you some hassle ;-)

Important Update: I just found out, that the new router I added in the abovementioned configuration breaks the regular delivery in certain cirumstances. I've already fixed it (again with help from Carsten) but I haven't updated the cookbook yet. I'm too tired...