What is the ruling on a girl marrying her maternal aunt's son or his brothers, and her sisters marrying them, if their grandmother breastfed her along with her maternal uncle and her maternal aunt's son?

If the grandmother who breastfed you is your mother's mother, then it is unlawful for you to marry the children of your maternal uncle (khāl) or maternal aunt (khālah), because your grandmother has become your mother through breastfeeding, and her children are your brothers and sisters through breastfeeding, and the children of your maternal uncle and maternal aunt are the children of your brothers and sisters through breastfeeding. As for your siblings who were not breastfed by this grandmother, it is not unlawful for them to marry the children of your maternal uncle or maternal aunt, with the exception of the son of the maternal aunt who was breastfed by the grandmother.

If the grandmother who breastfed you, your maternal uncle, and your maternal aunt's son is your father's mother, then it is unlawful for you to marry the children of your maternal uncle, and the son of your maternal aunt who was breastfed by your grandmother. As for your maternal aunt's other children who were not breastfed by your grandmother, it is not unlawful for you to marry them. Similarly, it is not unlawful for your brothers or sisters to marry the children of your maternal uncle or maternal aunt, except for the son of the maternal aunt who was breastfed by your grandmother, unless your sisters are from your mother only, in which case they may marry all of your maternal aunt's children.