Query Based Tab

I am trying to set up a query based tab, but my source is not directly connected to the destination.

We would like to create a QBT on our pay request bp.  The QBT would list all purchase orders.  Our pay request is created from the Contract SOV (which is created from Contract and updated with change orders)

The purchase order bp reference processes are for the contract or change order. 

Is there a way to create a QBT that would show all purchase orders for the contract and/or change orders on the pay request?