Let's say that, due to extraordinary timing, Team Cap meets at the airport but beats Team Stark there, allowing them to fly to their mission to stop Zemo. Somehow, they also manage to beat Zemo there, preventing him from killing the five Winter Soldiers. However, in a desperate move, he ends up activating them.
Instead of Iron Man and his team, Cap now has to fight five Winter Soldiers, who outclass Barnes himself. The arena is the bunker with the missile latch open. Everything within and outside the bunker is fair game.
Team Cap:
Captain America
Bucky Barnes
Hawkeye
Falcon
Ant-Man
Black Widow (since she betrayed Team Stark)
Who wins?