Not sure where to start but I want to create a New Field Name = Grouping ID during the load script.
If the "Price Disposed Date" is the same AND "Code CSW" is the same AND "Trade Type" is the same then take the last of the "IDs" in the Group and concatenate with C.
Example, Price Disposed Date = 30/8/16, Code = KW2, Trade Type = Sell, IDs 2811, 2819, 2824 then output for all IDs is C2824.
