Musnad Ahmad 28:171

Hassan narrated to us, Ibn Lahi'ah narrated to us, he said: Abdullah ibn Hubayrah narrated to us, from Abu Salim al-Jayshani, from Abdullah ibn Amr, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "It is not lawful for a woman to be married by the divorce of another [woman]. It is not lawful for a man to sell over the sale of his companion until he leaves it. It is not lawful for three people who are in a desolate land unless they appoint one of them as their leader. And it is not lawful for three people who are in a desolate land that two of them whisper to each other excluding their companion."