Understanding binds in Approval Workflow User List using both Users and Transaction Keys as Input

I have a workflow process for Cash Management in Financials 9.2 with PeopleTools 8.57 and want to limit the approval user list to a specifc role and not in the event log or the user that has selected the transaction from the settlement manager. I created a SQL object that joins PSROLEUSER and PS_CASH_FLOW_TR using the Transaction Keys but the User is not being pushed over to the SQL object even though I have the Include User as Input check box selected. PeopleBooks doesn't say much on how to achieve this and adding another bind value to the SQL doesn't