Change the default branch in the order line for intercompany repairs with non-stock lines

The first line in a repair (SR) order is the item that the customer returns. We use line type "R" which is setup as a non-stock line. The detail branch is the header branch.

We want to start with intercompany repair orders. For stock lines we use the inventory commitment preference to change the detail branch. But the inventory commitment preferences are not executed for non-stock lines. We tested the process by changing the "R" line type to a stock line. But this causes issues with commitments etc.

Does anybody nows another way to default the branch for non-stock lines?