Queues and DND

Hello everybody.
I am trying to create a really simple queue system for my office on TB 2.6.1.13. I only want one agent to be in each queue (actually, I want to create a queue for each agent, so the caller will be able to wait for a while, if the agent (i.e. our secretary) is busy). It all works great when the agents are actually busy. However, if they have activated their DND status, the queue thinks that they are available and still makes the caller hold the line for the designated time. I would like it if the queue skipped the agent and went straight to the fail over destination, if the agent is DND. I have tried every possible combination of settings in the queue, but have failed. Is there a way to do this?

The agents are static in the queues. I could make them non-static, but I wouldn't want them dialing 2 things every time they want to go somewhere (DND and logoff from their queue) and every time they come back.

Thanks