I need to filter out read, not read, recieved and delete receipts from
the inbox of a person in my organization. The person has calendar
delegates that have these tracking options selected by default, and
when they send meeting invites on his behalf, he gets a flood of read
(etc.) reciepts.

I was thinking of trying to filter by message class (I see all of
these fall into the "report.ipm.note" class), but can't figure out how
to do it. Any suggestions for the best solution to this problem, or
instructions on how to filter by message class would be appreciated!!