may be taking your example too literally, but is there a reason why you can't add a new attribute to the dim, have this effectively be a flag as to whether the member should be in this set (even if you simply put a right(field, 1). Set the attribute visibility to false but then use it within your query to filter the set? Doing the substringright/left on the inbound SQL will prob be faster than trying to determine it on ever single query run.