automatically download the attachment

Here's the deal

My boss wants me to make a mail on which our users will send an email with a certain attached file (a xml file) with some info. This has to be automatically downloaded and stored in a folder from which we can have access to it, besides, storing some of the file data on a database for consulting purpouse

The part i'm having trouble figuring out is, is there a way to have the attachment be downloaded once the mail is received, with no human intervention?

Given we are using Zimbra, maybe a Zimlets can be developed which will only work on this specific email, but then again, i need to know if its possible