Teams Structure

Looking for best practice on how to structure teams i.e I have an Accounts dept they have multiple locations and each location should only be able to see their own files yet management want to see all locations files.

Am I better off setting up one Team as below then adding private channels for each location restricting access to only people at that location and management?

Team - Accounts

Channel - General - All team members

Channel - UK - Only UK members and management 

Channel - Germany - Only German members and management 

Or creating a team for each location the question is then how will the management layers see files from all locations ?

i.e management layer would have to be member of 7 teams and would start to be messy