Queue should go to voicemail if Agent's phones are DND

I am attempting to get a queue to skip to voicemail when all agent’s SIP phones are set to Do Not Disturb. I have attempted to play with several settings within the queue, but I’m at a loss. When the Agent’s phones are set to DND, the hold music continues to play indefinitely like it normally would while ringing the phones.

it is not clear what problem you are trying to solve. typically if an agent sets DND, it should be for a short time (i.e. bathroom break, etc). otherwise they should log out of the queue. if you have agents logged into the queue the behavior of the queue is controlled by timing and capacity options. so for example, if the max wait time is set to unlimited and all logged in agents are on dnd, the caller will sit in the queue forever. DND, i think, simply indicates to the pbx that the phone is busy and should not be rung. so get your agents in the habit of logging in and out of the queues instead of using DND. put buttons on the phone for logging in/out to make it easy for them or give them isymphony or something similar that allows them to log in/out of queues on their screen. in fact if it is a union shop, you really want them to log out for their breaks thus providing evidence that they did in fact take their break