Generally, each side in a Dramatic Conflict picks one strategy and each side rolls for the effects using the Cooperative Skill Check rules on page 91.
What I don't understand is how you would run it for multiple people. The scenario I'm thinking of has 2 agents, each on snow mobiles, chasing 3 enemy snow mobiles. How would you structure this?
So in this case, the 2 agents form the Predator group and the 3 enemies are the Prey group. The Predator and Prey groups
each select a single strategy for the group. When the check is made, one character from each group becomes the leader and makes the skill check with each of the others in the group modifying the result per the rules on Cooperative Skill Checks on page 91.
For chases, if the predator wins, the leaders from both sides start the resulting encounter adjacent with all others beginning at a range from them based on table 5.1 on page 323. For arctic terrain this range is 4d6 x 10ft.
Alternative, if the prey wants to split up it could be run as 3 different chases with each predator picking which opponent they are chasing. In this case, one of the prey would get away as there aren't enough agents to chase them. Usually, I'd only do this if the Prey consists of special characters.
If renowned criminal masterminds, Tweedledee and Tweedledum, were being chased, they may split up and try to throw off their pursuers and plan to rendezvous somewhere later. Minion squad 17 would just stick together.