Here is a kb on the two types of selection architecture available in a GridGroupingControl.
http://www.syncfusion.com/support/kb/grid/Default.aspx?ToDo=view&questId=344If you are trying to select cell ranges, then you are using the selections inherited from GridControlBase. Here is a kb link on how to get these ranges. Replace gridControl with gridGroupingControl1.TableControl (as this is the GridControlBase object).