So in our organization, we have done away with Dropbox completely so that we can have a centralized way to manage the way our users share files and folders with OneDrive business that is included with our O365 service.
The way I am managing the permission and sharing is with 1 corporate account, managed by the IT department that has sub folders by name of department, as follows:
User = OurcompanyOneDrive@ourcompany.com
Folders:
Sales / Accounting / Operations
Those folder permissions are based on the AD group so if a user is added or removed, it will grand or revoke permissions accordingly.
In order to sync the new shared "folder" to the user in a specific department, I grab the URL, such as "https://mycompany.sharepoint.com/personal/ourcomapnyonedrive_ourcompany.com/Sales(or accounting, etc)
add add it as a new library to the users computer...