Do the sisters of the girl become محرمات (unmarriageable kin) by fosterage if the girl is nursed by her maternal aunt for four months?

Nursing does not establish sacred kinship (hurmah) with the wet-nursed child's ascendants and collateral relatives. Thus, his father, mother, and biological sisters remain non-mahram to his wet-nurse's husband, and her biological brothers and sisters. Therefore, you are not considered a mahram to your daughter's wet-nursed sisters, as long as they have not been nursed by your wife, mother, or sister.