Hardware: NEC DSX-40, 4 loop start lines, 8- 22 button phones, Intramail

The system is set up with the auto-attendant answering, then when a caller presses 1, all phones ring in Ring Group 1. If the call is not answered it goes to the Call Routing Mailbox #600.

Problem: The users want to see a flashing light on their phone when there are messages in this box. In the initial setup they saw a MW lamp only for their personal mailbox. In trying to make both types of messages show a MW lamp I changed the users to Group Mailboxes, which then showed MW lamp for the Group Mailbox, The Personal mailbox did not seem to be accessible (at least by outside callers transferred to a specific unanswered extension) in that setup. MW lamp is turned on for each extension and in 2213-04, and 2313-04.

How can I set it up to allow personal mailboxes and have message lamps for both types? The main MW lamp would be great, but could I use feature keys or a count on the LCD screen or anything?
Thanks,
GR