The members of all other party committees, and all other party officers, whose election is required by the party rules, shall be elected at the primary in the manner provided by this title; provided, that in any event, where the party rules provide for such offices, the national committeeman, the national committeewoman, the state chairman, and a district chairman each for the Islands of St. Croix, St. John and St. Thomas shall be elected at the primary election and shall serve for two (2) years, except that commencing with the year 1972 the national committeeman and the national committeewoman elected shall serve for four (4) years if the party rules so provide.