commission based on pricing discount

I am using JDE 9.1, for commission sales person is attached to customer but commission % I need to set based on pricing discount we are giving to customer

If customer discount is 20% commission will be 5%

If customer discount is 10% commission will be 7%

Higher the discount lower the commission offer. For Customer discount I am using cat code with 10, 15, 20 as UDC code to group the customer.

Please suggest a way if commission % can be based on customer cat code UDC value. and sale will be reflected in sales order.

Regards,

Anand