How do I IGNORE CPU alerts for specific hosts?

I have alerts setup for a specific page in Xymon.  There are certain host  that go Red and green throughout the day whichs sends out alerts.  The Wintel team is aware of the issue.  I would like to create an expection for these specific hosts not to send out notification.
 
I tried this based on documention i found but its not working. 
 
IGNORE HOST=$CPU_EXCEPTION SERVICE=cpu
        $NOTIFICATION_GROUP
 
Thanks