Is it permissible for my maternal cousin to marry me, given that my sister and my maternal cousin were both nursed by my mother?

"What is forbidden by lineage is also forbidden by fosterage. So, if a person is nursed by a woman, he becomes a son to her and to her husband, the owner of the milk. This applies only to the nursed individual, not to his siblings. Consequently, your paternal aunt's daughter being nursed by your mother does not make your paternal aunt's son a mahram to you. You may marry him if there is no other proven fosterage between you. The fosterage that prohibits marriage consists of five full, satisfying nursings."