Currently, there is no Drag and Drop support in the GridGroupingControl. This functionality will be added for a future release. It will not be in the 2.0 release though.
To implement this support, you can derive GridSelectCellsMouseController and override MouseDown, MouseMove and MouseUp to initiate a D&D operation yourself. Here is a sample that lets you select rows in a GridGroupingControl. Then if you mousedown on the selection, you can drag it to the GridDataBoundGrid or TextBox on the form, or you can drag it to Excel. This sample only puts Text in the DataObject, but you can add whatever data you want to drag.
forum_GroupingDnD_1907.zip