All proceedings and official action whatsoever, necessary to be taken under the contract or contracts made for such public improvements or works under this article, shall be taken and had by such joint meeting exclusively, except in matters relating to the raising and paying of money provided to be paid by the several contracting municipalities, and in all such last mentioned matters, each contracting municipality shall act in a separate corporate capacity, as provided in such contract, or by the laws applicable to each municipality.

All actions and proceedings of the joint meeting, pursuant to such contract between them, except as in this section otherwise provided, shall be considered and construed to be done by and under the authority of the respective contracting municipalities represented in such joint meeting, and as if done by each municipality in its separate corporate capacity, but no such municipality shall be liable for more than its proportionate share of the cost, damages and expense of said improvement or works as fixed by said joint contract.