I'm guessing you cant, because when you come to the server, all the others will have spawned, and they can't go back into the loading mission, so that would cause errors and everyone on that server would have their Blockland closed on them. SimpleWell HatMod is an add-on so they download it in the loading mission. Sorry, I can't explain very well. So all i'm saying is that the players that have spawned can't go to the loading progress and that would cause errors.