Is it permissible for a boy who was nursed by his grandfather's second wife to marry one of the granddaughters of his grandfather's first (divorced) wife?

If the grandfather's second wife breastfeeds her daughter's son from a previous husband with the grandfather's milk, this child is considered the grandfather's son through suckling. It is not permissible for him to marry the grandfather's granddaughters from his first wife, because she becomes his sister's daughter through suckling. It is stipulated that the suckling that establishes prohibition must consist of five full feedings.