Can someone please help me out?

I currently have a list of on which I currently have subtotals based on shop
Name, this gives me revenue by shops and total revenues. I am now required to
further show revenue by product type.

Example is set out below;

Shop Product Salesman Amount
AA Electrical SP1 10.00
AA Mechanical SP2 5.00
AA Electrical SP1 10.00
AA Total 25.00

BB Repairs SP4 10.00
BB Electronic SP4 20.00
BB Electronic SP4 10.00
BB Total 40.00

Grand Total 65.00

I would in the present scenario need a subtotal for Electrical and one for
Mechanical within subtotal for Shop AA and same thing for Repairs and
Electronic within subtotal for Shop BB.

Looking forward to receive your bright ideas and possible workaround.