8. A member of the Order carrying on professional activities within a partnership or joint-stock company must, to be authorized to carry on professional activities in accordance with this Regulation, furnish and maintain security on behalf of the partnership or joint-stock company, by means of an insurance or suretyship contract, or by joining a group plan contract taken out by the Order, against the liability of the partnership or joint-stock company arising from fault on the part of their members in the carrying on of their professional activities within the partnership or joint-stock company.