It seems to me you are successfully annoying the hell out of the two instigators as they seem to insist on bringing this up to you. I would continue to ignore the situation. The satisfaction that I've frustrated their best efforts to get me involved in their childish head games would be enough for me.

If SHE brings it up with you, just exclaim you have no idea what she's talking about, smile widely and wickedly and change the subject.

Works every time.