I shall recommend the use of purchasing units here. If this is a specific plant/ region, create a separate purchasing unit for the same and maintain the same in the csv you have mentioned. It will work.
Yes Anish as mentioned by Ravi you can use Purchasing Unit for this requirement but then the problem is you need to modify all you .CSV where you have Purchasing Unit.
In our case we didnt able to solve this at Purchasing Unit level also because we have different conditions at Commodity Code and Company code So we have asked to take this as CRD.