In many businesses, each physical location will be set up in D365 as a separate legal entity. There needs to be a method by which a centralized purchasing agency (at the headquarters, for example) can create a Purchase Order and then on the PO Lines, specify per line which legal entity the accounting (expense) needs to be posted to in General Ledger. This should be possible via two methods:

• Switching a PO line to a different legal entity switches Item Numbers and Product Categories available to those of the target entity, driving the correct GL and inventory posting. This allows centralized purchasing of both stocked and non-stocked items.
• Using Distribute Amounts to ONLY modify the accounting posting allows posting to different legal entity. This should only be allowed on non-stocked items, so that inventory cannot be posted to one entity while accounting posts to a different one. This would also allow accounting, by individual line, to be split across multiple legal entities by percentages.

In AP, it is possible on invoice journal invoices to make the Company field available on lines and the system automatically switches to the target company's account structure and chart of accounts, and assuming intercompany accounting is set up correctly, the system will automatically post the needed due to/from intercompany transactions. This is basically to add similar functionality to invoices created through purchase orders.