Section 91. All such caucuses of a political party for the choice of candidates for a city or town election, except caucuses relating to a special election, shall be held on the same day in each city and town. The city or town committee shall fix the days for holding all caucuses mentioned in this section, and all calls for the same shall be issued by its chairman and secretary. No two political parties shall hold their caucuses on the same day. The party first filing a copy of the call for a caucus with the city of town clerk shall be entitled to precedence as to the day so fixed.