Each health insurer and managed care corporation which is licensed to and does offer health insurance coverage in the individual market in this state shall as a condition of such licensure agree to participation in its respective assignment system provided by this chapter. This Code section shall not apply to an entity which offers only excepted benefits as specified in Section 2791(c) of the federal Public Health Service Act, 42 U.S.C.A. Section 300gg-91(c).