Switching between JMS Queues in real-time

Hi All,
I tried to find an answer to this question with no luck so far. The scenario that needs to be implemented is as below:

• There is a BPEL service consuming messages from Queue A
• In an emergency outage scenario, there is a need to repoint that BPEL service to Queue B (then vice versa after outage complete).
• Queue A will continue to accept messages as they arrive
  
• This needs to be handled in real-time by the Apps Support team so this needs to be:
• Relatively easy to do
• Robust enough to make sure the environment does not fall over