Hi Harshad,
Here is a forum thread that shows you "How to avoid the 'jumps' while the user changes the value in a sorted column?". It is implemented in GridDataBoundGrid. Similar way you can implement this tech in a GroupingGrid. Please try this and let me know if this helps.
http://www.syncfusion.com/Support/Forums/message.aspx?&MessageID=51318Best regards,
Haneef