How to provide a fixed transfer price for an item at the Source org/destination Org

We have an item which needs to be transferred from INV ORG 1 to INV ORG 2. Both orgs have periodic average costing method enabled.

But this item cannot be transferred using the current setup which is at opening cost of the item. Nor It can be transferred at cost plus margin basis via transfer pricing rules as the price is volatile with no set pattern to calculate and can change/vary in a vast range.
We have also tried adding a Ship through order management step in the supply chain orchestration so that we can edit the price of the sale order level, but it has not helped us as price in uneditable in the internal sale order line level.