Are the younger individuals considered foster siblings to one another if the mother breastfed some of the خالَة's children and the خالَة breastfed some of the mother's children?

Those two who suckled from your mother became your siblings through suckling, all of you, but not the rest of their siblings. And your two brothers became siblings to all the sons and daughters of your maternal aunt, because they suckled from her. The criterion is sharing the same breast.