(4) This Agreement shall not apply to legislation on social security of the Institutions of the European Communities or to any convention or agreement on social security which either Party has concluded with a third party or to any laws, orders or regulations which amend the legislation specified in paragraph (l) for the purpose of giving effect to such a convention or agreement but shall not prevent either Party from taking into account under its legislation the provisions of any other convention or agreement which that Party has concluded with a third party.