VPRS value to be copied for another condition type during sales order punching

In sales order,I have a

condition type with condition category 'J-Customer Expected Price'. The value for this condition type will be same as VPRS

(i.e Cost maintained in Material Master)
During punching of order I want the system should

automatically pick the VPRS value for this condition type.
This will save my time of maintaining the record

through VK11 and there will be no chance of maintaining incorrect record.

How should I develop this?