Add a new row to each group by section

[ramyakrish85]

I had posted this question on stackoverflow but did not get any answers. I want to be able to add rows below each 'group by' when I click on add new button next to group header

The problem is this always adds row to top or bottom of the whole table and doesnt take into account last row in the group after which I want to add this row.

table.addRow({field0: "US",field1:'',field2:''}, false , lastRowOfClickedtheGroup)