Requiring health maintenance organizations (HMOs) that have entered into a risk-sharing contract with the federal Health Care Financing Administration to provide health care services under the Medicare program, to offer the contract in all jurisdictions of the State, and to consider the entire State a single service area for purposes of determining premiums; and requiring HMOs that have entered into such a contract to establish the same premium for all enrollees if the HMO establishes or alters an already established premium.