Hi Abhilash,
Thanks for your help. It really worked except I am still stuck in the last step. I am getting the following formula in Edit Insertion Formula:
GetRowGroupIndexOf(CurrentRowIndex) = 1 and GridRowColumnValue("@Event Year") = "2013"
(my Year indicating field call @Event Year, it's from formula editor). When I replaced the 'Date' with '@Event Year' in your formula, it did not work. Can you please help me a bit more. Here is my table how it exactly look now: