I played this yesterday at work for some pre-Christmas fun. Worked quite well, although not everyone got what was going on...
I emailed a load of people I thought might be up for it, split the ones who were into two teams and BCC emailed the separate teams with instructions, so everyone knew which team they were on but not who else was on their team.
I made them email me when a kill was made and updated the results on a spreadsheet. There was only one same-team kill in the end and one team ran away with it due to one particularly skilful and stealthy Ninja. Ran all afternoon, everyone enjoyed it. Our office has multiple floors so I think that worked better.