There shall be not more than 2 associate members of each board appointed
under this chapter and chapter 7, other than the zoning board of appeals,
who shall be eligible to participate in all board matters. The chair
of the appointed board may designate the associate members to sit
on the board in the case of absence, inability to act or conflict
of interest, on the part of any member of the appointed board or in
the event of a vacancy on the appointed board. The associate members
shall be appointed for 3-year rotating terms by the board or officer
responsible for appointing the board itself and any vacancies arising
in said position shall be filled in the same manner as the original
appointment for the remainder of the unexpired term.