Is the girl whom the mother breastfed along with her daughter considered a sister to all the mother's children from her first and second husbands? And are the daughters of this girl considered nieces to the mother's children?

Nursing establishes the same prohibitions as lineage. So, whoever nurses from a woman becomes a child to her and to her husband, the owner of the milk. If your mother nursed a girl, then this girl becomes a sister by nursing to all your mother's children from her first and second husbands; this is because the milk is attributed to the mother. Consequently, your maternal aunt whom your mother nursed is considered a sister to all of you by nursing, and all your children will be maternal uncles and aunts to the daughters of this sister. The nursing that establishes prohibition must consist of five full feedings within the first two years of the child's life.