No member of a board of chosen freeholders during the term for which he is elected shall be eligible for appointment to any office or position required to be filled by the board unless he shall resign and cease to be such a member at least 3 months prior to his appointment, except in cases where such office or position, by law, may be filled by a member of the board or the appointment is to the position of county counsel or county treasurer.
N.J.S. § 40A:9-23