(1) Each employer shall offer no less than once every year to every employee and dependent entitled to receive health care under an existing health benefit plan supported in whole or in part by such employer the opportunity to become enrollees in certified health maintenance organizations which have the capacity to provide basic health services in health maintenance organization service areas in which at least twenty-five such employees reside: Provided, That nothing herein shall require an employer to contribute more on behalf of an employee seeking to enroll in a health maintenance organization than would be contributed on the employee's behalf to the existing health plan.
