Which marriage is valid when a woman has two guardians (waliyyan) who marry her to two different men?

Primary text

If a woman has two guardians and permits both to marry her to whomever they wish, and they contract two marriages to two different men, the marriage contracted by the guardian who acted first is the valid one, even if the second guardian had intercourse with her, unless the second guardian had sexual intercourse, in which case the second guardian takes precedence. This view is held by Al-Hasan, Al-Zuhri, Qatadah, Ibn Sirin, Al-Awza'i, Al-Thawri, Al-Shafi'i, Abu 'Ubayd, and the People of Opinion, including 'Ata' and Malik (with the caveat regarding prior intercourse). The evidence cited is the statement of 'Umar: 'If two guardians contract marriage, the first is more entitled, unless the second has consummated it.' The rationale for the second being entitled if consummation occurred is that his contract was followed by possession (qabd). The primary evidence is the Hadith: 'Any woman whom two guardians marry, she belongs to the first,' narrated by Abu Dawud, Al-Tirmidhi, and Al-Nasa'i from Samura and 'Uqbah.