The Commission shall appoint one of its members as chairman, one of its members as vice-chairman, and one of its members, or any other competent person, as secretary of the Commission. The chairman of the Commission shall serve for a term of two years and until his successor is appointed and qualified. The vice-chairman shall likewise serve for a term of two years and until his successor is appointed and qualified. The office of chairman of the Commission shall be rotated among the representatives of the three constituent appointing public bodies, so that a representative appointed by each constituent agency shall hold office as chairman for a term of two years, and the first chairman so appointed and serving shall then be succeeded by a representative appointed by a second of the two remaining constituent appointing bodies. Upon the expiration of the second two-year term, a representative of the third appointing body shall be elected as chairman to hold office for a term of two years. The pattern of rotation as thus established shall continue in order that no representative of any of the three constituent appointing bodies shall hold office for a full two-year term unless two full intervening terms shall have expired. In the event that the office of chairman shall become vacant, the duties of the chairman shall be temporarily performed by the vice-chairman, but a successor shall be appointed as expeditiously as possible from the members representing the same constituent public body as did the former chairman who shall have failed to complete his term. Insofar as is practicable, the same scheme of rotation shall be applied to the office of vice-chairman, but the practice of rotating the office of vice-chairman may be dispensed with, in the event that the Commission, by a two-thirds vote, shall find that the rotation of office is impracticable. Office on the Commission shall be deemed an office of honor within the meaning of the provision of Section 1A of Article 17 of the Constitution of South Carolina. The secretary of the Commission shall have such term as shall be fixed by the Commission.