The best way is to have Sun and Beast pair together, and Chalice and Axes paired together.
For each pair, one person shoots the upper most that isn't called by the runner, and the other shoots the bottom most one not called by the runner.
Example; Runner calls Sun Top, one person will shoot the middle as it's the upper most, and Beast will shoot bottom.
You're basically covering 3 buttons with 2 people and reacting to a call by shooting the ones that aren't called.
You also only need to be on your button to shoot if your symbol is called.
Sun can shoot Beast from the ground, and vice versa.