When i had my parrots and they were being overly aggressive, i did not flush them, couldnt do that to any live animal, i found a home for them, my sister in law took them, and they are happy in the tank they are in.
Just make a decision as to what to keep, or separate them and put them in a different tank from the ray. If you are like most of us in here, you more than likely have many or a few extra tanks floating around that can be put to use in emergencys or in the case like you have.
Good luck
Regards Novaman