inter-office; inter-location; inter-company
Refers to activities, communication, or movement between different business offices or locations, often within the same company or between companies.
Communication between offices is done by email.
I was ordered to transfer between offices.
事業所 means a business office or establishment; 事業所間 adds the suffix 間 (between) to indicate inter-office relations.
Compound of 事業所 (business office) + 間 (between).