(a) a party may respect such an institution or person to recommend the names of suitable individuals to act as conciliator, or

(b) the parties may agree that the appointment of one or mom conciliators be made directly by such an institution or person: Provided that in recommending or appointing individuals to act as conciliator, the institution or person shall have regard to such considerations as are likely to secure the appointment of an independent and impartial conciliator and, with respect to a sole or third conciliator, shall take into account the advisability of appointing a conciliator of a nationality other than the nationalities of the parties.