Hi Bernhard,
Thank you for your interest in Syncfusion products.
We suspect that you need to group a column and customize the group caption with only the item name. The GridGroupingControl have built-in support for grouping and the caption can be customized by using the CaptionText property. We already provided a knowledge base document to achieve this scenario. Please make use of the below UG and KB link for further details.
Please let us know, if you have any other queries.
Regards,
Arulpriya