Contract Pricing Procedure should be picked for PO based on Contract

I have created a contract which has a custom Pricing Procedure.When I create PO with reference to this contract, then currently the conditions maintained in pricing procedure of contract as well as the pricing procedure of PO is picked by the system.

In case of PO based on Contract only Pricing Procedure of the contract should be picked up by the system instead of pricing procedure of PO.

Is there any config changes to be done to achieve or we will have to go with ABAP changes.

Please help.

Regards