Is it possible to have a separate row for the unassigned lot quantity in a saved search?

I half-suspect that there is a trivial solution to this that I just don’t have enough experience to spot. I’m trying to run a Saved Search to show the Quantities of assigned and unassigned Lot #s within SO transaction lines, split by Sales Order / Document ID. In other words, each row would basically represent:

I’d like to see output that looks like the following mock-up:

The problem I’m running into: I cannot figure out how to surface the unassigned entry as its own row, where unassigned (the quantity out of the current transaction line that is not yet assigned to a Lot) is essentially treated as its own unique Lot # within the transaction line. This is especially problematic when a single transaction line has a subset of its quantity set to a Lot # and the remainder