Not to exceed twenty-four Members of Congress shall be appointed to meet jointly and at least annually with representatives of the Chamber of Deputies and Chamber of Senators of the Mexican Congress for discussion of common problems in the interests of relations between the United States and Mexico. Of the Members of the Congress to be appointed for the purposes of this subchapter (hereinafter designated as the United States group) half shall be appointed by the Speaker of the House from Members of the House (not less than four of whom shall be from the Foreign Affairs Committee), and half shall be appointed by the President of the Senate upon recommendations of the majority and minority leaders of the Senate from Members of the Senate (not less than four of whom shall be from the Foreign Relations Committee). Such appointments shall be for the period of each meeting of the Mexico-United States Interparliamentary group except for the four members of the Foreign Affairs Committee, and the four members of the Foreign Relations Committee, whose appointments shall be for the duration of each Congress. The Chairman or Vice Chairman of the House delegation shall be a Member from the Foreign Affairs Committee, and, unless the President of the Senate, upon the recommendation of the Majority Leader, determines otherwise, the Chairman or Vice Chairman of the Senate delegation shall be a Member from the Foreign Relations Committee.