Is it permissible for me to marry my maternal aunt's daughter with whom my sister was nursed, or any of her other sisters?

Your maternal aunt's children, both males and females, are considered foster siblings to your sister, who was suckled by their mother. As for you, you are not considered their foster brother as long as you were not suckled by their mother. Thus, your maternal aunt's daughters are not forbidden to you, and it is permissible for you to marry one of them, even if she is the one who was suckled alongside your sister.