Joe,
Is there a way in your software to make the return address something other than KappaPerformance@yahoo.com? If you were to make the return address KappaPerf.noreply@yahoo.com or something, it would get bounced and then perhaps those users would read the emails completely.
Either that or maybe configure the "PM waiting" email so it doesn't quote the text of the message but just states that a PM is waiting.
Just a thought...
Bob