Section 5. Any medical organization shall consist of not less than five physicians who are duly registered to practice in the commonwealth and who are members of the Massachusetts Medical Society or other recognized association of physicians, or are members of the staff of any hospital approved by the American College of Surgeons. Any medical organization may enter into an agreement with any duly registered physician whereby such associated physician agrees to furnish medical services to the subscribing members of a medical service corporation with which the medical organization has an agreement and whereby such associated physician agrees to accept as payment for said services a proportion of the funds received by the said medical organization from the said medical service corporation. Such agreement to accept payment for services shall provide for payment according to units of funds received by the said medical organization and shall not provide for specified amounts, whether according to the services rendered by the said physician or otherwise. Nothing herein shall change the normal relations between patient and physician nor prohibit any medical organization from employing a medical director and assistants, or nurses, or establishing a clinic for the rendering of medical services. Any such agreement between a medical organization and its associated physicians shall be subject to the approval of the department of public health.