Section 53A. A superintendency district formed and conducted under the provisions of section sixty, or a superintendency union formed and conducted under the provisions of sections sixty-one to sixty-four, inclusive, may employ one or more school physicians and may employ one or more school registered nurses; determine the relative amount of service to be rendered by each in each town; fix the compensation of each person so employed; apportion the payment thereof among the several towns; and certify the respective shares to the several town treasurers. A school physician or registered nurse so employed may be removed by a two thirds vote of the full membership of the joint committee. The joint committee of any superintendency union may employ clerical and secretarial help, special teachers and supervisors, fix the compensation of each person so employed and apportion the payment thereof among the several towns; and certify the respective shares to the respective town treasurers.