Automatic email response for GROUP mailbox not personal inbox

Hi,

My team has a central group team mailbox called 'CENTRAL APPROVALS' - there
are 9 on our team and everyone has access to this mailbox. The problem is,
certain emails which arrive in the team mailbox are marked 'Private' and we
can't see them (even though the number shown says '9', there's only actually
'6' in there for eg).

We would like to generate an automatic email response for every email that
comes into the team group box to inform users that if they have marked their
emails as 'Private' to re-send without the Private marking.

How do i create this automatic email responder? I know there's an Out of
Office for my own email account, but i don't want it to affect this.

thanks!