It’s the “and shipped by” that makes these two separate sales orders, one in each company.
The two companies in Epicor are as different as Amazon and Temu. They may happen to share a database, but they are completely separate and distinct.
Company 1 will have a sales order for Part X, and will ship Part X, and the revenue and cost will show on Company 1’s financials. Company 2 will have a sales order for Part Y, and will ship part Y, and the revenue and cost will show on Company 2’s financials.
To have a single sales order, then only one of the companies will have revenue from the customer. Say Company 1 gets the sales order for parts X and Y, but company 1 only makes part X and company 2 makes part Y. In this scenario, Company 1 makes part X, and creates an intercompany purchase order to buy part Y from company 2, which then creates a sales order (with customer company 1) for, makes it, “ships” it to company 1, who then ships BOTH parts x and y to the original customer.