I'm making a duel plugin where players can duel other players. When you right click an item, it opens a menu for you, and if you click on for say a carrot, it will add you in the queue until someone else joins in it. How would I make this happen so it match makes and stuff with the opponent also wanting to duel? I don't want to make possibly 100 arraylist's or something like that. Ideas, information, and help is appreciated!