Hi John,
Thanks for your interest in Syncfusion product.
If your intention is to show the different combobox values in the same column then you have to set different data source of the comboboxes. You have to handle QueryCellStyleInfo event to achieve this. I have attached the sample for your reference.
http://www.syncfusion.com/Support/user/uploads/GGC_Combo_eb5531fa.zipPlease refer to the sample and let me know if you have any questions.
Regards,
Nagaraj