What happens if the husband's older wife has five daughters who suckle the young wife from their mother's milk?

Primary text

If the husband's older wife has five daughters with milk, and they suckle the young wife to the extent that one of them establishes herself as the young wife's mother through suckling, then the young wife's mother (the older wife) becomes forbidden, and her marriage is invalidated. There are two narrations concerning whether the young wife's marriage is also invalidated.