How to prevent users from combining multiple Sales Orders in a single shipment?

Summary:

Content (please ensure you mask any confidential information):

As per our solution, one shipment can have only One Sales Order shipment lines. How to prevent users from combining shipment lines of multiple sales orders in a single shipment?

Version (include the version you are using, if applicable):

26A

Code Snippet (add any code snippets that support your topic, if applicable):