Sum of Amount group by Currency

Hi,

In my report I want to show sum of amount by currency code. But my amount is display field. Anybody have any idea.

Customer Account Currency Amount
1101 USD 100
1102 USD 200
Total 300

1103 INR 200
1104 INR 200
Total 400

Check how the amount is getting calculated in the display method… use same logic to get amount sum by relating the custAccount and currency.