I'm not 100% sure that it's possible in the current engine.
Opponent Override is overriding the opponent as soon as a move's animation frame gets to a certain point regardless of it hitting or not. Mainly useful for Throws and Cinematics.
What you'd be looking to do is funcitonally what only a throw is able to do. You'd have a move which would be the animation if it doesn't connect with the opponent, and then upon hitting (Active Frames > Hit > Throw Move Confirm) it will perform another of the same character's moves which is set up to do the Opponent Override when performing the "Throw Landed" animation.
So let's assume you could get an attack into that state, you'd have the animation of the attack whiffing (base animation let's say with frame data 5(2)16), from there you'd need an animation of the recovery frames which are the last 16 frames of the animation to be its own move with no active. That recovery frame move has an Opponent Override that plays another move file that has the 'being hit' animation with no active frames either. Also, be aware that that situation would also require you to set the positioning from the attacking player to move the opponent to when the hit occurs.
So it WOULD be possible if this feature wasn't limited to Throws at the moment. Note, you could get it to work if you have a throwable collision box whereever the opponent's hurt boxes are, but you'd again be falling victim to the properties of a default throw which means they'd be unblockable.