Is it permissible for the children of a sister to marry the children of her brother, whom her mother breastfed?

If a brother breastfeeds from his sister five times before weaning, he becomes her son by fosterage. Her sons and daughters then become paternal uncles and aunts to his sons and daughters. And his sons and daughters become nephews and nieces to her sons and daughters. Consequently, marriage between their children is not permissible, due to Allah's saying: "Prohibited to you are your mothers, your daughters, your sisters, your paternal aunts, your maternal aunts, the daughters of your brother, and the daughters of your sister" [An-Nisa:23], and due to the Prophet's (peace and blessings be upon him) saying: "What is prohibited by lineage is prohibited by fosterage."