Change sender address   

I have Exchange Server 2000 on Windows 2000 Server. Client Outlook 2000 Pro

I need when user sends mail, automatically change his address to group 
address.

Example:
Group1: group1@domain.com
   |_ User1: user1@domain.com
   |_ User2: user2@domain.com

When User1 sends mail his Reply Address must be group1@domain.com.

Thanks

Sorry for english, my languaje is spanish.

date: Tue, 3 May 2005 13:05:02 -0700   author:   Germán Enriquez (ARG)