Any one or more adjoining or adjacent counties or municipalities including any municipality within any such county may by agreement provide for a joint local planning commission for any two or more of such counties and municipalities. The agreement shall provide for the number of members of the commission and how they shall be appointed, in what proportion the expenses of the commission shall be borne by the participating localities, and any other matters pertinent to the operation of the commission as the joint local planning commission for the localities. Any commission so created shall have, as to each participating locality, the powers and duties granted to and imposed upon local planning commissions under this chapter.
Va. Code § 15.2-2219