SCOM 2007R2 create a rule using OR AND

Hi,

I am trying to create a rule to monitor errors in the event log but filter out those we know about.

Whenever I create an OR group followed by a series of AND groups once I save it combines the first to AND groups and removes the OR?

I have completely different checks within each AND so it's not like they could be in the same AND group.

Help, it is making me go mad

OR group (any of these are true)
  AND group (all of these are true)
  Event Level Equals Error
  EventID Equals 22
  AND group (all of these are true)
  Event Level Equals Information
  EventID Does not equal 11

once saved becomes

AND group (all of these are true)
  Event Level Equals Error
  EventID Equals 22
  Event Level Equals Information
  EventID Does not equal 11