Is it permissible for me to marry my maternal uncle's daughter, knowing that one of my brothers was suckled by her mother, and my mother suckled one of her brothers?

There is no harm in marrying the daughter of one's maternal aunt if the suckling of one of the brothers by her mother only affects him, making your aunt a mother to him, and her children his siblings. Likewise, if the suckling of one of the girl's brothers by your mother only affects him, then your mother becomes his mother and her children his siblings. It is stipulated that the suckling must occur within the first two years of life and consist of five or more distinct feedings.