Hi James,
If you want to have an multiple header row, then you can have a custom section and in that you can have a header row. Here is a forum thread with a sample.
http://www.syncfusion.com/support/forums/message.aspx?MessageID=38487Also, refer the CustomSectionInGroup sample in the browser samples.
[instal drive]\Syncfusion\Essential Studio\4.1\Windows\Grid.Grouping.Windows\Samples\CustomSectionInGroup
Best Regards,
Haneef