Easiest way is to host a game, set the game to private then get all the stats as high as you can. Do this in each of the category's mentioned above. When your happy with your stats make the party open and let people join. As someone enters start a challenge. People cant break your scores whilst in a challenge so just make sure that everyone in the party is in a challenge. If someone joins half way through stop the current challenge and start a new one. once 8 people are in the party you should get the achievement.