Odoo enterprise v 18.4 
Hello,
Let me set the scene:

I have two warehouses:

1. Warehouse SB

This is the main warehouse, which receives and ships goods (see screenshot of warehouse SB).

2. Warehouse DC

This is a secondary warehouse used to store surplus stock.

It is sometimes selected as the delivery location for purchase orders, but it is never used to ship goods to final customers.

Please ignore the third warehouse 3EXT shown in the screenshot. It is not relevant to this scenario and would only add unnecessary complexity.

Configured Routes

For Warehouse SB, I have configured a supply route from Warehouse DC:

• Pull From 2DC/Stock → 2DC/Output

  (Method: Take from stock; if not available, trigger another rule)

• Pull From 2DC/Output → Inter-warehouse Transit

  (Method: Trigger another rule)

• Pull From Inter-warehouse Transit → 1SB/Stock

  (Method: Trigger another rule)

Problem Context

I have a product with:

• 100 units in SB

• 100 units in DC

We receive a sales order for 300 units.

What I want Odoo to do:

• Take 100 from SB

• Take 100 from DC and transfer them to SB

• Then purchase 100 for SB to cover the remaining demand

What Odoo actually does:

• It takes 100 from SB

• It creates a need for 200 in DC, so it pulls 200 from DC and sends them to SB

• Since DC only has 100, it creates a purchase of 100 for DC, to fill the artificial shortage created there

Question

Does anyone know how to achieve the intended scenario, where the remaining quantity is purchased for SB, not DC?

Thanks in advance!