What is the ruling on the marriage of six sons to their maternal aunts' daughters, knowing that the mother breastfed three of her elder sons along with her brothers, and she also breastfed her brothers along with her three elder sons with satiating sucklings?

If a mother breastfeeds her older sons five known feedings, she becomes their mother through suckling, and they become brothers to her daughters. Thus, it is impermissible for them to marry their daughters' daughters, according to the Prophet's saying: "What is prohibited by lineage is also prohibited by suckling." However, if a sister breastfeeds her brothers, but not her sisters, there is nothing to prevent her younger sons, who were not suckled, from marrying their maternal aunts' daughters. The prohibition only pertains to the older sons.