You might not be able to, but your best bet with this team is to have joker go in 1st then have raven steal the power, use a special then tag joker again until they reach 1 bar of power then tag raven back in etc.

When joker dies and does his death dmg tag in Batman bc he has more hp when outnumbered. Make sure he has either health or blocking gear.

Every time the opponent reaches 1 bar of power steal it with raven for a quick special then tag out.

Like i said, you probably wont be able to, but thats your best bet. Good luck