Any two or more towns, cities or boroughs having economic development commissions may, by ordinance adopted by each of them, join in the formation of a regional economic development commission. The area of jurisdiction of the regional commission shall be coterminous with the area of the municipalities so joining. Any municipality which has joined in the formation of a regional commission may thereafter withdraw by the adoption of an ordinance to that effect. The economic development commissions of the municipalities comprising the regional commission shall jointly determine the membership of the regional commission. A regional commission shall have the same duties and authority, in respect to its area of jurisdiction, as a municipal commission has in respect to the municipality. Each municipality may annually appropriate to a regional commission a sum which, in addition to any amount appropriated to its municipal commission, will not exceed one-twentieth of one per cent of its last-completed grand list of taxable property.