Question Some help with Worldguard and regions etc.

So I'm quite new, and I've been searching through the internet for hours without any good explanation on how to do my following requests.

So I wanna make a region, I only want a special group to build in that region, how would I do that?

I'm using the latest version of PermissionEx and Worldguard & Worldedit(if that's neccesary).
I've made the groups: Owner, Admin, Moderator, Member.
I only want Admins to be able to build in the area.

Two more questions.
My Permissions.yml: http://pastebin.com/uJeAsfJJ
1. Could someone take a look and tell me why my moderators can't turn on and off gamemode?
Do I have to give them essentials.* or what? Because essentials.gamemode.* doesn't work

2. Why can't I kick my admins or my moderators? it jusytsays "you can't kick this player"

 

You can set the owners of a region to be a group
/region define NAME g:GROUPNAME

1. did you give them just essentials.gamemode , you could also try Bukkit.command.gamemode

2. It's probably because they have the permissions essentials.kick.exempt , just remove that permission from them