grouping of fields based on a unit price in a subreport of crystal report

In the below picture I have two items,whose cost values are different and the respective unit of the cost is also different

I want the output , like I have shown in the below picture

The detail part should split based on the cost unit,how can i do this ?

I am trying to do in subreports and i am not getting how to insert group inside of subreports?