How to trigger a drop ship by SO Line or automatically

Hello,

We have two drop shipping scenarios and would like to know how to configure them:

Scenario #1: Whenever a customer orders items (123,456, or 789), if insufficient inventory is available, the orchestration process sends a request to create a requisition to Procurement (the PO is created manually or auto-created.)

• How do we accomplish this in the system? I am already familiar with Sourcing rules and plan to use a "Buy from" Sourcing rule type, but I am uncertain if Oracle will use this rule if there is insufficient inventory or will GOP use this sourcing rule reg In other words, we want GOP to check for available on-hand inventory and, if none is available, use the drop ship flow.