in message
Can one set up vacation email to let those in the company know
you're
out for a 1 week vacationand to refer to a co-workers, but not for
external emails (discussion groups, news signup, etc)?
That should be the normal configuration within Exchange. When using
Exchange as the e-mail server, and, I believe, with the default setup,
the OOO (Out Of Office) replies should only be sent to Exchange
subscribers (i.e., employees within the same Exchange organization).
A company does not want to look stupid in not being able to cover for
employee absences or termination in not having a suitable alternate
assigned to accept those e-mails. A company also doesn't want to help
spambots determine which are valid e-mail addresses.
Talk to whomever is the Exchange admin at your company. They'll know
if the auto-responder in Exchange is configured to deliver those
auto-replies to only other Exchange subscribers or if they are allowed
for externally received e-mails.