DURATION in alerts

I have an alerts file where hobbit sends out an alert to a ever-widening group of people based on DURATION... the longer the un-ack'd duration, the more excited it gets.

The problem comes in when something goes YELLOW for a while and then goes RED.  All the time it spent at YELLOW is included in the DURATION even through I have a COLOR=red explicitly given in the config file.

Is there a way to specify the duration as the time something has been RED as opposed to NOT-GREEN?

Thanks,
Jon