Approver determination for Fiori Approve Purchase Orders

Hi Experts,

We have set up the standard Fiori Approve Purchase Orders application and are able to access it from the Launchpad.

I have a question pertaining to the approver determination in the Fiori app - in our case the release strategy is not constant and we are determining the approver users from an exit dynamically on the basis of cost center, material group and total amount of PO.

So we cannot maintain the entries in the table in SPRO -> Materials Management -> Purchasing -> Purchase Order -> Release Procedure for Purchase Orders -> Define Release Procedure for Purchase Orders -> Workflow.

With this, how can we make sure that the corresponding workitems are shown for the approver users when they open the Approve PO Fiori app? Currently even though the approver user has some POs pending in the SAP Inbox, the same are not being fetched and shown in the Approve PO Fiori app - the count of workitems in the app tile is shown as 0.

Regards,

Saurabh