Hard code a dial plan for user mailbox access

I have an AA50. All users voicemail goes to ext 601’s mailbox. All other extensions need to be able to access this extensions mailbox. I edited each extensions mailbox to point to mailbox 601 in the users.conf file. All of the phones now get a notification when a voicemail is left in 601. When I try accessing the voicemail from another extension it asks me to type in the mailbox number (601) and then it lets me log in to hear the voicemail message. Is there a way around having to type in the mailbox number (601) to listen to the voicemails left at ext 601?

The extensions don’t want there own voicemail box, they all want to share mailbox 601.
I was told I needed to hard code the dial plan to do this and I don’t know how I would go about doing this.

Any help will be greatly appreciated.

Thank you

First parameter of VoiceMailMain()