One mailbox for 2 different users

[beirut]

I am trying to find a solution for 1 user, who has 2 different sets A and B .
and assign him one mailbox, to both sets.
I created a ghost Z user, Forwarded to voice mail. And associated this Ghost Z to A and B.
Voice mail is going to sets, but the supervision light or mailbox key is not flashing. That is normally expected with such configuration.
Is there a way to make the Mailbox flash when getting a voice mail in such scenario, or is there another way to make this configuration?

[Mr T]

I believe you can make mwi light for any extension on 4635 only.

On either 4635 or 4645 systems you can program a voicemail supervision key that will light up when there are voicemails in the ghost z mailbox.