Are the maternal uncle's children considered siblings through suckling, thus prohibiting marriage to them, if the eldest brother was suckled by the maternal uncle's first wife, while the suitor is the maternal uncle's son from his second wife?

"What is established by suckling is established by lineage. Thus, the suckling child becomes a son to the woman who nursed him and to her husband, the owner of the milk. The prohibition is exclusive to the suckling child himself, not extending to his brothers and sisters. Therefore, your brother being nursed by your maternal uncle's wife does not make your maternal uncle's children forbidden to you [as mahram]. It is a condition for suckling to establish prohibition that it consists of five full, satisfying sucklings."