The co-operation on the international space station is specifically between the partners of the station: Canada, the U.S., Japan, the European Space Agency and Russia. All operations of the station and the participation of these nations in the program are guided by that agreement.
I think we are still, it's fair to say, some years away from nations that want to participate in the peaceful exploration of the moon forming a partnership. It might be something that will come in the future. It might involve the participants that are currently collaborating on the international space station and perhaps beyond that, but at the moment, it is not yet formalized or in place.