individual - location-type work address
Let me think a bit on how I would tackle this. I suppose that if I was only interested in the work addresses of Steven and Thomas I would simply add the work address on the Individual contact level. If I am however interested in the employer/employee relationship as well I can see no other option than having each branch as an Organisation. I would probably add a contact_sub_type for this, something like 'local organization' with a relationship 'Local Branch of' with the main office so I have the whole pattern clear.