Trouble programming PEX and GriefPrevention

On my Pixelmon server I run PEX and Griefprevention. I created an admin claim around the spawn and when my friend joins to test it he can break blocks. How do I set this up so he cannot break blocks in my admin claims? Also I was sondering if anyone knows a good permissions file for PEX with Pixelmon that I could use I see a lot of permissions files for PEX around but haven’t found one good for Pixelmon yet. Finally I wanted to ask about a few PEX commands.

  1. I have added myself (the owner) to 2 groups admin and owner and the only prefix that shows up is admin and id like to remove myself from admin so I’m only an owner how do I do this? Secondly how do I add permsissions to a group for instance as of right now the default group cannot use /kit starter.
    Thanks for all the help!