JDE orchestration: P4950 how to map route from form W4950A to form W4950B in form request

We are trying to build a form request to update existing routes but we are stuck on the fact that in JDE, when we are in the inquiry page (form W4950A), we can filter out a single route, but on select to go to the update form W4950B, JDE display all the routes for that origin/Carrier/mode of transport. Then the form request does not know anymore which line it's supposed to update.

We tried using process recorder but it's just trying to force a row-number-for-update, which could easily change. How could we pass some filtering information like route number, which is unique, to W4950B  to indicate which line to update?