mysql query performance... got to be a better way
this is josh.  Try the following 

SELECT  b.minID, a.AssociatedObjectID
FROM    tableFromAbove a
        LEFT JOIN
        (
            SELECT AssociatedObjectID, AssignmentSubType, AssignmentValue, OwnerUsergroupID, MIN(AssociatedObjectID) minID
            FROM tableFromAbove 
            GROUP BY AssignmentSubType, AssignmentValue, OwnerUsergroupID
        ) b
            ON a.AssignmentSubType = b.AssignmentSubType AND a.AssignmentValue = b.AssignmentValue AND a.OwnerUsergroupID = b.OwnerUsergroupID
            WHERE minID &lt;&gt; a.`AssociatedObjectID`;