This was essentially the plot of an original series Star Trek episode, https://en.wikipedia.org/wiki/A_Taste_of_Armageddon:

  In this episode, the crew of the USS Enterprise visits a planet whose people
  fight a computer-simulated war against a neighboring planet. Although the
  war is fought via computer simulation, the citizens of each planet have to
  submit to real executions inside "disintegration booths" to meet the casualty
  counts of the simulated attacks.