Notifiy rule for public folder container

We have a Public Folder called Out of Office which contains messages that a user can post when they are out of the office. We have some users that would like to be notified when an e-mail arrives in the public folder. How can I get this public folder to notify certan users when an e-mail arrives in this Out of office folder? either through a Outlook rule or from Exchange ?
We would prefer doing it throught Exchange.

Running A.D. Exchange 2000
Users using Outlook 2000 and 2002

Thanks