If the articles of incorporation or action by the board of directors pursuant to section 30-29-602, Idaho Code, authorizes dividing the shares into classes or series, the articles of incorporation may also authorize the election of all or a specified number of directors by the holders of one (1) or more authorized classes or series of shares. A class or series, or multiple classes or series, of shares entitled to elect one (1) or more directors is a separate voting group for purposes of the election of directors.