[crpatino]

Make the bonus pool a fixed percentage of company yearly profits (not sales). Assign at least half of the bonus pool in an egalitarian way (like based on the number of days worked on that year), assign the remainder on a roughtly "merit" based criteria, and let every team to agree on the criteria, but make it be something objective (it does not matter if it is number of bugs closed, or being at your desk on time in the morning, or whatever, just as long as the measurement is unambiguous and the team agrees on it).

That would be far from perfect, there will be free loaders, and most likely than not it will be slightly unfair to everyone. But at least you have removed the perverse incentive to sabotage coworkers in order to look yourself better.