Batman, Nightwing and Red Hood vs Ozymandias, Nite Owl and Owl Man
Batman, Nightwing and Red Hood (Batman: Under the Red Hood)
Versus Ozymandias, Nite Owl (Watchmen) and Owl Man (Justice League: Crisis on Two Earths)
All are at full strength. Morals are off (Batman will kill.) All are armed with any and all weapons/gear/gadgets from their movies. Obviously this applies to weapons/gar/gadgets that they can carry on them. Both sides are 100% familiar with the other.
Scenario one: Fight takes place in New York's subways, with trains coming and going every few minutes. Stalking battle, they must hunt each other down and kill. They start one mile apart.
Scenario two: Straight up brawl in Ozymandias's lair.