(1) Any city, county, or town or any combination of cities, counties, or towns wishing to be represented upon an existing planning board may, by agreement of the governing body or bodies then represented on the board, obtain representation on the board and share in the membership duties and costs of the board upon a basis agreeable to the governing body or bodies creating the board.
(2) The membership, as well as the jurisdictional area of any board, may be increased to provide for representation and planning of any additional cities, counties, or towns seeking representation.
(3) Any city, county, or town that becomes represented upon an existing planning board pursuant to this section may appropriate funds for expenses necessary to cover the costs of representation. Subject to 15-10-420, the governing bodies of any represented city, county, or town may levy on all property that is added to the jurisdictional area of an existing board by representation a tax for planning board purposes under procedures set forth in Title 7, chapter 6, part 40.