Can we create PO for a dummy organization and create release for organizations when vendor is ready?

Currently we place individual POs to our 4 warehouses and the supplier decides in which order to fill the orders. In the current process, ship to organization is mandatory.

We have a need to send one PO to the supplier and when the supplier is ready to ship, they will notify us and need a way to release the PO with quantities to be shipped to each of the warehouse

Example: we place a “blanket PO” for delivery 90 days out and then as the supply is ready to ship, we decide where to send the product to on multiple deliveries.

Can you please let us know how to accomplish this