Hi Premila,
Thanks for your interest in Syncfusion products.
I have created a minimal sample to show your desired behavior. Here is the sample:
http://websamples.syncfusion.com/samples/Grid.Windows/Grid_WF_GGCChildTableSorting_I46505/main.htmPlease check the sample available in the above link and let me know with more details if I am misunderstood your requirement.
Regards,
Subhasheela R