Display only the first record

I have report in BEx where we want to find the first time a customer ordered Quantity of more than 500 in a data range (For Ex: From April 10 to April 30). In a particluar date range the customer may order more than once (Qty > 500). The catch is we want display only one first time he ordered qty > 500.

Customer Date Qty > 500.

ABC 4/21/2005 2,035 CA

4/22/2005 12,290 CA

4/23/2005 4,826 CA

4/26/2005 6,397 CA

4/27/2005 1,538 CA

4/28/2005 4,849 CA

XYZ 4/25/2005 2,000 CA

4/26/2005 12,000 CA

4/27/2005 4,500 CA

4/28/2005 6,300 CA

....

In the output report we want to display the first record for each customer as:

Customer Date Qty > 500.

ABC 4/21/2005 2,035 CA

XYZ 4/25/2005 2,000 CA

Your help is really appreciated. Thanks.