Sayyiduna Ubadah bin al-Samit (may Allah be pleased with him) says: Among the rulings of the Prophet (peace and blessings be upon him) is that he ruled, regarding two grandmothers in inheritance, that the one-sixth would be divided between the two of them.
Al-Tabarani recorded it in al-Mu'jam al-Kabir, and Ahmad recorded it within a long hadith. The chains of both are munqati' (broken): the narrator Ishaq bin Yahya did not hear from Sayyiduna Ubadah (may Allah be pleased with him).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفرائض / 7161