You could automate your replenishment to default to Dropship for the Products in question (those that can be delivered either way).

Doing so will create a Purchase Order upon adding a Product to a Project Task, with the "Deliver To" field being set to "Dropship" by default. If for some Sale Order you don't want that to be the case, simply change it to "Receipts" before confirming the Purchase Order.

Defaulting to "Dropship" will prevent Odoo from putting together multiple Purchase Orders from different Customers.

Such a Sale Order could look like this:

Step 1: Confirm Sale Order with just "a project task" Product

Step 2: Add "a stock product" Product to the Project Task -> Odoo will create a Purchase Order defaulting to "Dropship"; Confirm it to have your Dropship delivery on the Sale Order

Step 3: Add the same (or any other) Product to the Project Task -> Odoo again will create a Purchase Order defaulting to "Dropship"; This time, change it to "Receipts" and you'll have a Delivery Slip on the Sale Order

Hi,

In Odoo, managing inventory and sales for businesses that use both internal stock and dropshipping can be challenging, especially when working from the Project module. Dropshipping is a fulfillment method where products are shipped directly from a supplier to the customer, rather than from your own stock.

When creating quotations from a project task, Odoo automatically assigns a route (such as Dropship or Buy) and locks it, preventing manual changes. This can be inconvenient for projects that may sometimes deliver from stock and other times via dropshipping, depending on the type of project (residential vs. industrial).

Refer:https://www.odoo.com/documentation/19.0/applications/inventory_and_mrp/inventory/shipping_receiving/daily_operations/dropshipping.html

Hope it helps