No. An organizational unit determines which services and features are available to a set of users.
An access group turns on a service for a group of users within an organizational unit or across different organizational units. You can turn off a service for the organization, and then add specific users to an access group that has the service turned on.
A configuration group customizes settings for a group of users within an organizational unit or across different organizational units. For example, you might use configuration group to review and approve YouTube videos for your organization.