Si elles n'y arrivent pas, elles devraient alors convenir mutuellement d'un arbitre auquel on présenterait les éléments sur lesquels on s'est mis d'accord, ceux sur lesquels on n'arrive pas à s'entendre, et la position finale des deux parties en la matière.
If they couldn't settle their disputes, they would then have to mutually agree to an arbitrator who would be presented with the things they had agreed on, the outstanding things they had not agreed on, and their final position on both of them.