Create fake bounce / NDN

[Fnordbert]

I have a 3letter-domain for which I have a "wildcard receiver account". Mail to all non-existent users at the domain end up here. This is very convenient to make up addresses for registrations at sites I don't trust etc. This account receives a lot of spam of course, and I'm well aware that it would be pointless to bounce these as the sender is usually fake.

From time to time however, there are some typos which are obviously intended for real humans, miss-typed CCs on long email chains etc. I can't really be bothered to interact with these people and explain their mistakes, but it would be nice to be able to create a filter to respond with a fake Non-Delivery-Notice. (like they would get if I disabled the wildcard-account) It would not need to be a "real" NDN that would fool a Postmaster, it would only need to be good enough to make the senders get the point.

Would it be possible to do this with the current functionality, perhaps with SmartTemplate, or Javascript? If not perhaps this could be added as a feature request?