Thanks for using Syncfusion products.
We have analyzed your requirements. Unfortunately, GridGroupingControl doesn’t has support for exporting selected records and exporting multiple grids to single Excel file. All the records of a single Grid only can be exported to excel with or without its styles. For further more information about exporting, please refer to the below user guide documentations,
Please let us know, if you have any concerns.
Amal Raj U.