I have created a custom form for replying to messages when I am out of the
office.  I also have a rule set up so that I can only respond to messages
with the custom reply when I'm scheduled to be out of the office.  However,
this means that everyone who sends me an email will get a reply, even if I
have already replied to an earlier email sent by the same person.

I would like to have the following sequence triggered for all incoming email
messages:

1) Check the sender's email address against the email addresses in a special
contact folder.
2) If it is in the special contact folder, don't respond.
3) If it is not in the special folder, respond with a custom "out of the
office" message and add the sender's email address to the special contact
folder.

Can someone point me in the right direction or offer any suggestions?

Thanks