I'm using AimTrain by hoppel on my server to run aimtrain arenas full of bots, instead of having a giant list of the names of each arena I'd like to use a portal system to teleport players from the lobby directly to the arena they want. However the way you join an arena is by typing /at "arena name".  The arena is its own instance where no one can see you, and you cant see other players. I've tried using the Portals plugin by Laserhydra, but it didn't work. Zone manager also doesn't seem to have anything to help here. The only way I can think of teleporting a player in there using a portal would be to run the /at join command with one, but I'm not sure how I would do this. Does anyone know a way to do this? Thanks!

You can call the method in the other plugin  generally, which you can see how to do in the Docs.