The arguments provided by the GroupElementFormatting event provide access to the data object of the current PivotGroupElement. Knowing that object and depending on your business logic you can modify the visual appearance of the group element: Formatting Appearance. Please also check my snippet below:
I am also sending you a screenshot showing the result on my end.
I hope this helps. Should you have further questions please do not hesitate to write back.
Regards,
Hristo Merdjanov
Telerik
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