21.4.0.2. A corporation that would be controlled by a group of persons, in this section referred to as the “first-tier group”, if no corporation that is a member of the first-tier group were controlled by any person or group of persons, is controlled by(a) the first-tier group; and
(b) any group of one or more persons comprised of, in respect of every member of the first-tier group, either the member, or a person or group of persons by whom the member is controlled.