Coordination rule.
Coordination rule. A taxpayer shall be treated for purposes of this paragraph (f) as owning a substantial indirect interest in each of two or more undertakings for any taxable year in which
(A) Such undertakings are treated as part of the same activity of the taxpayer under paragraph (f)(2)(i) of this section; and
(B) The taxpayer owns a substantial indirect interest (within the meaning of paragraph (f)(3)(i) of this section) in any such undertaking.