Purchase Order feature - Split shipment from Vendor

We are looking for the ability to enter tracking information for only a certain quantity of the total requested quantity of an item on a Purchase Order. For example; A PO is created for 100 connectors, and the Vendor ships 10 connectors under "xxxxx" tracking number, and another 90 connectors on a different tracking number at a later date. Currently the workaround would be to adjust the quantity on the PO from 100, to 10, add the tracking number for the 10 and "save and Close", then go back into the project and it prompts to update the order status on 90 of the 100 connectors (since they were removed from the PO). Following this we would go back into the PO and re-add the 90 connectors from the project and then add a distinct tracking number and ship date.

It would be great if this function could be done directly in the PO window.