I think you could modify the
Shield Bash script to do this.
Pretty much what the Shield Bash script does is whenever the user presses a certain key combination, it finds all the people within a certain radius from the attacker and plays the "falling over" animation. You could modify it so that instead of playing an animation, it deals damage. You could even make it only deal damage to enemy units, or not deal damage to enemies that are defending and other stuff like that. Of course, the Shield Bash script is for .960 and I personally don't know how compatible that is with 1.003.