It is narrated from Sayyiduna Uqbah bin Amir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When two guardians (separately) marry off (the same woman), then she (the marriage) belongs to the first one."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15030