(a) (1) Two or more counties may jointly establish county alcohol and other drug programs pursuant to Article 1 (commencing with Section 6500) of Chapter 5 of Division 7 of Title 1 of the Government Code.
(2) Any county may, by contract, furnish alcohol and other drug services to another county.
(b) Unless otherwise expressly provided for or required by the context, this part relating to county alcohol and other drug programs shall apply to alcohol and other drug programs operated jointly by two or more counties.