Vacation has to respond to the MAIL FROM address or Return-Path address,
not to the Reply-To/From header.
You probably need a way to specify the delay between repeat notifications
if it's not the default one week. I'm not sure how important this is.
I suggest you drop the recipient check, but instead use Sieve to do the
recipient check in examples. The Sieve interpreter may not know all the
address forms for the script owner.
The man page on vacation does a good job explaining the services it
provides. It's fairly complete and well designed.
- Chris