METADATA-COLUMN_GROUP is not getting
as per RETS doc METADATA-COLUMN_GROUP defines grouping element which should be used to group columns together in any GUI system that is designed in order to satisfy the display requirements of an MLS. But when i am tryting to get it like getmetadata?Type=METADATA-COLUMN_GROUP&Format=COMPACT&ID=0&rets-version=rets/1.7.2
Response is <rets replycode="20501" replytext="Type parameter: METADATA-COLUMN_GROUP is invalid"> </rets>
How to get the grouping of fields of each type of class for one property.?