If otherwise lawful, any 2 or more associations may merge or consolidate under this chapter or under the law of the state where the surviving or new association will exist. Before an association may merge or consolidate with any other association, a written plan of merger or consolidation shall be prepared by the board of directors or by a committee selected by the board or the members of the association. In case of consolidation, the plan shall also contain the certificate of organization of the new association. The members, or such stockholders as are entitled to vote thereon, shall approve the plan in the manner provided in N.H. Rev. Stat. § 301-A:8 for amendments to the certificate; and the plan, as approved, shall be filed with the office of the secretary of state. The secretary of state shall charge and collect a fee of $25 for the filing of the plan with his or her office.