No hospital service corporation shall issue group contracts which are not experience rated pursuant to section 5 of this act, until it shall have filed with the commissioner a full schedule of the rates which are to apply to such contracts. The commissioner may disapprove such schedule at any time if he finds that such rates are excessive, inadequate or unfairly discriminatory. It shall be unlawful for any corporation to effect any such group contract according to such rates thereafter.
N.J.S. § 17:48-6.5