; and (C) necessary to effect the purposes of this section. (d) Facilitating cooperation The Secretary, acting through the Centers for Medicare & Medicaid Services, shall develop and disseminate best practices that will serve to facilitate cooperation with, and agreements between, States and the Service, Indian tribes, tribal organizations, or urban Indian organizations with respect to the provision of health care items and services to Indians under the programs established under title XVIII, XIX, or XXI of the Social Security Act . (e) Agreements relating to improving enrollment of Indians under Social Security Act health benefits programs For provisions relating to agreements of the Secretary, acting through the Service, for the collection, preparation, and submission of applications by Indians for assistance under the Medicaid and children’s health insurance programs established under titles XIX and XXI of the Social Security Act , and benefits under the Medicare program established under title XVIII of such Act, see subsections (a) and (b) of section 1139 of the Social Security Act . (f) Definition of premiums and cost sharing In this section: (1) Premium The term premium includes any enrollment fee or similar charge. (2) Cost sharing The term cost sharing includes any deduction, deductible, copayment, coinsurance, or similar charge. . 154. Sharing arrangements with Federal agencies Section 405 of the Indian Health Care Improvement Act ( 25 U.S.C. 1645 ) is amended to read as follows: 405. Sharing arrangements with Federal agencies (a) Authority (1) In general The Secretary may enter into (or expand) arrangements for the sharing of medical facilities and services between the Service, Indian tribes, and tribal organizations and the Department of Veterans Affairs and the Department of Defense. (2) Consultation by Secretary required The Secretary may not finalize any arrangement between the Service and a Department described in paragraph (1) without first consulting with the Indian tribes which will be