Universal Containers has a requirement to share Accounts automatically to the users at a field office. They currently have the following setup in their environment:
* Accounts are set to Private in the Org-Wide Default.
* The field office is specified by a lookup in the Account object.
* There are 400 field offices.
* The users in each field office are managed using public groups.
Based upon a lookup relationship field on the Account, how should the Architect meet this requirement?