Link between Back-to-Back Sales order and PO

We have a requirement to develop a report to find-out Open PO's (and corresponding requisitions) for a Back-to-Back sales order that are cancelled.

We are trying to build a query that links all the lines on a back-to-back sales order to corresponding SO lines. After going thro couple of Documents on oracle support portal, it doesn't appear to me that there's a direct way of linking them

Checked this link below, but the query in there have links as below

What OE Header or OE Lines Table Column Links Back To A Purchase REQ for Back To Back Orders? (Doc ID 734460.1