Yeah, so i'd really want to know if i can somehow do this "You need to have rank X to continue."
Im doing a prison server and im building these areas to the prison where you could only go there if you have high enough rank. Can i somehow do this? Because my problem now is that everyone, even lower rank players than rank X are able to go to the area. And i dont know how to do this correctly. So if you know, please help. 
AND I USE SPIGOT/BUKKIT. I wasn't able to choose that.
