I need to find a way to forward a modified version of all new messages. Essentially, all mail that comes to Zimbra will have a corresponding email that goes to a secondary address. The secondary messages will all be the same and say something like "You have new Zimbra mail". Of course, each user will have a different secondary email address (which will be obtained from OpenLDAP).

Any thoughts on how to best to do this?

I thought about creating a postfix proxy to intercept incoming mail that could handle generating the forwarded message. But, it would be nice if there was a simple way to do this with Zimbra.