You can probably use the lost focus event in SO Entry for the ship to address lookup (lku) using Customizer. 

If you go into the Customization main form and click the Help button, you can read some of the "How Do I..." sections to see how the relationships are made and fields linked together. You don't want to save fields, so you will need to adjust, such as locking the field, but for example, the "Define a Data Binding Relationship" shows how to relate fields (and link them). There are other ways, but this should show you one example. 

Darrick