Put an extension, say 301, in group 505. Should be the only extension there. Set overflow in 505 to 1 sec. Make sure you have the no answer greeting recorded for mailbox 301.
In mmc 502 set no answer forward for 301 to 1 sec. In mmc 722 put an mw button set to 301 on the extension to be used to monitor the general mailbox.
Should work great.
