I'm hoping to set up some kind of mail interceptor for a friend who uses his Gmail account for professional purposes. He is working only half-time for 6 months, and is not able to keep up with the mail coming in. Much of the email he receives ought to be handled by someone else.
So what I want to do is create an auto-bounce that anyone who tries to email him will get (probably only the first time) saying, X is on part-time leave, and does this email really need to go to him, and give them a list of other people they should be emailing about various issues that my friend is not handling during his leave. And then give them some way to say "yes, really deliver this message" or to back out and not send it.
I know I have had friends who set things like this up on private email servers, but I can't immediately think of a good way to do it using Gmail. Any thoughts?