Hi Stuart,
This can be achieved by having a custom comparer and specifying it to the particular GroupedColumn in GridTableDescriptor. This was shown in the sample code.
GridGroupingControl1.TableDescriptor.GroupedColumns[0].Comparer = new YourComparer();
GridGroupingControl1.TableDescriptor.GroupedColumns[0].Categorizer = new YourCategorizer();
Also refer this KB article:
http://www.syncfusion.com/support/kb/grid/Default.aspx?ToDo=view&questId=147Best regards,
Haneef