You can use a .forward file to forward mail to an address outside of Courant. Forwarding mail to another machine at Courant will result in an alias loop due to the existence of your global alias. So beware.
To forward all your mail to an outside address from your CIMS address, simply open the .forward file in your home directory. Modify the file so that it contains only the e-mail address that you would like all your mail to be forwarded to. If you want to disable mail-forwarding, simply delete the file, or leave it completely blank.