Question Need help with PEX and ChestCommands

Hey, I am currently working on a small server, and I use both PermissionsEX as well as ChestCommands.

The problem I am facing is that when you try to buy something (this does not apply to Op's) it says "I'm sorry,but you do not have permissions to preform this command. Please contact the server adminisrators if you believe that this is a mistake." I do understand that it means that they do not have the right premissions but I dont want to give them the permission permanently because then they will be able to perform /execute and /pex commands.

Is there a way to give them permission only when they are in the CC menu and then remove it when they exit.

Help would be much appreciated!