If your instance of The Layer has sub companies configured, you can link them to specific warehouses.
This determines:
The default sub company assigned to a stock item when it is booked in
The sub companies available when reallocating an item of stock
The default selection of sub company in the menu when reallocating an item of stock from a work stack
From Settings - Sub Companies, you can see a list of configured sub companies. Click on one to view its settings.
The Warehouses menu lets you choose warehouses that are valid for this sub company. You can select multiple warehouses.
You can also select a Default Warehouse for the sub company.