Mont. Code Ann. § 35-17-410

Any association may upon resolution adopted by its board of directors enter into all necessary and proper stipulations, agreements, and contracts and arrangements with any other cooperative corporation, association, or associations formed in this or in any other state for the cooperative and more economical carrying on of its business or any part or parts thereof. Any two or more associations may by agreement between them unite in employing and using or may separately employ and use the same methods, means, and agencies for carrying on and conducting their respective businesses.