question

Hi Irving, thank you for your question.

 Does this primary designated user have a need for a voicemail box? If not, you can turn off messages within this user's extension, then route all unanswered calls to a call queue, as you mentioned.

 If this primary user does in fact need a voicemail option when calls go unanswered, it is best to create an advanced rule within the user's extension that they can turn on when away. This advanced rule would be set up to ring the other users when turned on.

I think I understand.
The user does have a need for voice mail.
Now when the user activates the DND button her calls to her extension or DID go to VM.  Calls from the press of "0" go to a group.

Correct, if the only device in the user's call handling is in "DND" mode, their calls will immediately go to voicemail. To avoid this, the user can enable an advanced rule that would send all calls to a group (this would require the user to log into their extension to make this change rather than hitting "DND" on their device. Please refer to the following knowledge article for instructions on how to create an advanced rule within a user's extension: 
http://success.ringcentral.com/articles/RC_Knowledge_Article/How-to-access-the-advanced-call-handlin...

I follow what you are saying.
But we would want the normal calls to user extension that were from DID or dialing of extension number to go to user's VM.

We want only the auto-attendant calls to by pass the user and go to the group.
Here is the scenario

Outside caller dials one of 4 DID's. > Attn-attendant answers> caller can enter an extension #, can get a company directory, can leave a "company" VM or press '0"> if "0" is pressed call goes to ext.1123 and rings at ext. 1123> if 1123 answers the user then has all of the options available as to any other call, if user does not answer it goes to user's VM, to keep from going to user's VM the User enacts DND and the calls are then directed to a group

I see. Unfortunately, the DND mode will simply bypass the phone. There is no way to reroute calls based on this setting. Calls will continue to ring to ext 1123's VM even in DND mode.