Multiple "Required By"/Next Delivery dates per PO

I'm looking to request a feature that will allow us to have more than one Required By date on an Advanced Purchase Order. Or even, just multiple Delivery Dates per PO.

Each of our purchase orders do not equal one shipment, so I would like to see a Required By date added to the Invoicing & Receiving portion. (image 1)

This way, I can record what is coming in on the next shipment for a PO (we can prepare our invoice), and enter a date for when these products will arrive. 

If a product is on more than one PO or more than one Invoice in the same PO, the Next Delivery on the Product Availability page would take into account which date is first. (image 2)

This would give us an accurate glance of when a product is coming in next without having to search the rest of our system (many spreadsheets) for it. A cherry on top would tell you the quantity coming in next.

We also export Product Availability to update other platforms with the availability and next delivery date and right now we are having to do the delivery date manually because we can not use the "Required By" date in a PO, because not all products are coming in on that date.