Hi Marcus,
Thanks for your interest in Syncfusion products.
As per the GridGroupingControl current behavior, the records will be filtered based on the checked item of the GridExcelFilter popup from the FilteredRecords collection. So, the multiple column filtering will be applied from the already filtered records. Moreover, we have checked for the possible cases to achieve your scenario (i.e. to filter the records with “OR” operator). We regret to let you know that the GridGroupingControl does not have any direct support or extensibility to achieve your scenario.
Please let us know if you have any other queries.
Regards,
Sindhu