Section 62F. Any two or more such cities or towns may vote to form, for such period of time not exceeding five years as such cities or towns may from time to time determine, a union children's health camp district for the purpose of establishing therein one or more union children's health camps. The management of such union children's health camps in such district shall be vested in an unpaid commission, called the commission on union children's health camps, to consist of the following persons from each of the cities or towns constituting such union, namely, the mayor or chairman of the board of selectmen, who shall have no vote, the superintendent of schools, the members of the board of health, all to serve, ex officiis, and also not exceeding ten members, residents of the cities and towns comprising the district, to be elected by the ex officiis members of the commission for terms commensurate with the duration of the agreement forming or continuing the union. The term of each person elected to fill a vacancy among the members not serving ex officiis shall be for the balance of the unexpired term. The treasurer of said commission shall be the treasurer for the time being of such city or town within the district as is determined by the members of the commission. The provisions of sections sixty-two C to sixty-two E, inclusive, so far as applicable, shall apply to such commission.