No group life insurance policy or certificate shall contain any provision that reduces or denies any benefit otherwise payable because a pre-existing medical or health condition contributed to the death or disability of the insured. No group life insurance policy or certificate shall contain any provisions that exclude benefits for specified illnesses or medical conditions of the insured or which impose additional waiting periods for pre-existing conditions or specified illnesses or medical conditions of the insured. An insurer may require that an insured be actively at work in order to be eligible for any benefits of the policy or certificate.