For your stock you could run an open PO Orders Detail Report, Export to Excel and filter on the PO#. This will show you the items that are on the PO and not received yet. It does seem like there should be a filter in the QB Reporting that would also allow you to do the same but I didn't see an option for doing that in QB.

You could also clean up the exported excel and do your own pivot table but this would be rather time consuming, especially if you are a retail store with many orders to monitor!