It is narrated from Ibrahim (may Allah have mercy on him) that the Messenger of Allah (peace and blessings be upon him) made three grandmothers heirs to the sixth. The narrator said: I said to Ibrahim (may Allah have mercy on him): Who were they? He said: Two from the father's side and one from the mother's side.
This is mursal (disconnected). It has also been narrated through Abd al-Rahman bin Yazid from the Prophet (peace and blessings be upon him), and that too is mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12348
It is reported from al-Hasan (may Allah have mercy on him) that the Messenger of Allah (peace and blessings be upon him) "made three grandmothers heirs."
This too is mursal (disconnected), and it supports the first one; and it is what has been narrated from a group of the Companions of the Messenger of Allah (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12350
It is reported from Muhammad (may Allah have mercy on him) concerning four grandmothers that Sayyiduna Umar (may Allah be pleased with him) placed them all equally in the sixth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12351
It is reported from al-Sha'bi that Sayyiduna Ali and Zayd bin Thabit (may Allah be pleased with them both) used to make three grandmothers heirs: two from the father's side and one from the mother's side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12352
Kharijah bin Zayd (may Allah have mercy on him) narrates from his father (may Allah be pleased with him): If the deceased leaves three grandmothers of the same degree, and there is no mother or father besides them, the sixth will be for all three of them; and they are the maternal great-grandmother and the paternal great-grandmother.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12353
Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: Three grandmothers will inherit: two from the father's side and one from the mother's side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12354
It is narrated from Sayyiduna Abdullah (may Allah be pleased with him) that three grandmothers will inherit: two from the father's side and one from the mother's side.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12355
It is narrated from al-Sha'bi (may Allah have mercy on him) that four grandmothers came together to Masruq (may Allah have mercy on him). He set aside the mother of the maternal grandfather and made the three grandmothers heirs.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12357
It is narrated from al-Sha'bi, and from Humayd from al-Hasan, that both of them said concerning the mother of the maternal grandfather that she does not inherit.
It is narrated from al-Sha'bi: Her son, who is nearer than her (to the deceased), does not inherit, so how can she inherit?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12358