Hi,

Odoo’s standard procurement rules are limited when it comes to multi-warehouse fulfillment. “Resupply from Another Warehouse” only works for one warehouse, and standard MTS/MTO routes often duplicate moves instead of splitting demand properly. This makes it impossible to automatically fulfill a sales order from multiple warehouses without custom logic.

The cleanest solution is to implement a custom procurement rule or a dedicated route. This rule would check available quantities in warehouses by priority, then split demand across them as needed — for example, first pulling from Warehouse A, then Warehouse B for the remainder, and so on. This ensures quantities are balanced correctly and respects FIFO if based on lots/serials.

Other approaches, like resupply or virtual warehouses, won’t handle this use case cleanly. If development isn’t an option, third-party Odoo apps exist that already implement advanced cross-warehouse allocation. But for full control and FIFO compliance, a custom stock rule or route extension is the most reliable way forward.

Reference:

* https://www.cybrosys.com/blog/how-to-set-up-and-control-odoo-18-resupply

* https://www.youtube.com/watch?v=5KjbxYNlQ9k

* https://www.cybrosys.com/odoo/videos/v17/inventory/how-to-manage-buy-to-resupply/

Hope it helps

Customer is in German.