Simplified Workflow Rules with Group First Responder and Supervisor Hierarchy in the same block

We are defining Payables Invoice Workflow rules using Spreadsheet and have Group First Responder and Supervisor Hierarchy in the same block. In this case, the Supervisor Hierarchy is pulling the right people, but they are getting notifications in parallel instead of serial. I have tried playing with Rule Priority on both of these but has now worked. Has anyone been able to accomplish this?