Hi Vladymyr,
Thanks for your interest in Syncfusion Products.
You can hide the table in the GGC, by having a customengine. Derive the GridChildTable in the CustomGroupingEngine and override the GetVisibleCount(), there check for the tablename you want to hide through the ParentTableDescriptor.Name and return 0.
Please refer the below sample that demonstrates this
http://www.syncfusion.com/Support/user/uploads/GGC_HideTable_fd9f811a.zip Let me know if you have any other questions.
Have a nice time.
Regards,
Rajagopal