| Object Model > GroupColumns Object |
When the DataView property is set to 2 - Group, a grouping area is created above the list; columns may be added to this area to form a group, creating a new split in the list. Each column that is placed into the group becomes a member of the GroupColumns collection, while remaining a member of the Columns collection. If the column is removed from the GroupColumns collection, it is returned to the list; it is not deleted.
The OLE DB TDBList control maintains a GroupColumns collection to hold and manipulate grouped columns. This collection is accessed using the GroupColumns property.