What is the ruling on the marriage of the questioner and his younger brother to their paternal uncle's daughter, given that the questioner's two older brothers were suckled by his paternal uncle's wife, and that his paternal uncle's two sons (the young men) were suckled by the questioner's mother, and that the suckling was full and repeated from both parties?

Your two brothers nursing from your uncle's wife makes them foster sons to your uncle and his wife, and thus they become foster brothers to your uncle's children. Likewise, your mother nursing your uncle's two sons makes them foster sons to her and your father, and thus they become foster brothers to you and your siblings. As for your uncle's daughter, who did not nurse from your mother, she is a stranger to you and your younger brother, because fosterage is specific to the nursed child himself and does not extend to his siblings.