Any county that adjoins a county having an established community mental health services program may elect, by a majority vote of its board of commissioners, to join that established community mental health services program. The joining must be approved by the board of commissioners of each county already participating in the established community mental health services program, and the joining shall become effective on January 1 following the date of final approval. Upon the joining, the board of the established community mental health services program shall be dissolved, and a new board shall be appointed in the manner provided in section 212 and 214.