Hi Mark,
Thank you for your interest in Syncfusion products.
The Grouping operation can be performed only depending
upon the columns value. It would not be possible perform group operation
depending upon within the column values. If you would like to perform grouping operation
for 'Letter, Drawing, Image' , we would suggest you to make the column values
values “Letter”, “Drawing”, “Image” seperately instead of giving coma delimited
list like 'Letter, Drawing, Image”.
Please let us know if you need any further assistance.
Regards,
Asarudheen.