So this summer I am running a tournament for our entire circle of gamers. We have 16 players expected to show up and will be using two DMs. We will be splitting the players into groups of 8 (competing guilds) and they will be entering a recently found dwarven mine at separate entrances. They will have 1-4 group encounters a piece before both teams converge (hopefully) in the same large room. Just before things escalate to much the thought is to create a challenge(s) they will all need to work together to get past. Has anyone ever tried anything like this? I am looking for any suggestions or ideas. Thanks!