A unit that begins its movement stacked with another unit may leave the hex without penalty. If there is more than one enemy-occupied HEX at which a friendly unit can fire, the unit must choose one hex.
Artillery combining fire with infantry units also cause any indicated step losses.
Since the distance from the lower hex to the woods is one hex, and two hexes from the higher hex to the woods, LOS is blocked. The artillery could also fire at a CSA unit in hex 2917, because the distance from the lower hex to the woods is greater than the distance from the higher hex to the woods. Face the retreating unit in the direction of the hex it enters, and maintain facing until the next movement opportunity. Advance all attacking units from any one attacking hex. Recovery does NOT count against the two Action limit for the Command's leader and units.