If there was a zip code that was just virtual PO Boxes, it could use the existing change of address machinery to slap the actual delivery address on when addres

If there was a zip code that was just virtual PO Boxes, it could use the existing change of address machinery to slap the actual delivery address on when addressed with a virtual box. Assuming they used an entire sectional center facility for it, you could have 100 zip codes, with 6 digits of unique delivery points, so 100 million virtual boxes.