subtotal of every 2 rows beneath them.

[harshpahuja]

	Price	Count	Total Price
Product A	1	2	3
Product B	1	2	3
Subtotal A+B	A1+B1	A2+B2	A3+B3
Product C	1	2	3
Product D	1	2	3
Subtotal C+D	C1+D1	C2+D2	C3+D3
Product E	1	2	3
Product F	1	2	3
Subtotal E+F	E1+F1	E2+F2	E3+F3

How to achieve this above kind of subtotal of every 2 rows beneath them?