PEX Rank Please Help

DONATER
I would like Brute to inherit Default
Elite inherits Brute and Default
Beast inherits Elite,Brute and Default
Barbarian inherits Beast, Elite, Brute, and Default
STAFF:
I would like Helper to inherit Default
Moderator inherits Helper and Default
Admin inherits Moderator, Helper, and Default
Owner is by himself.

I want it so through buycraft (Where Command is used to rank players to the bought donator rank)
A command such as /pex user <user> group set <group> Is used or something similar so I can have that preset so it will be automatically done through Buycraft.

ISSUE:
Currently Default rank works fine, commands and etc..
However as soon as I use '/pex user <user> group set <group' And rank a player to ANY RANK besides from 'default' whether from ingame or console that rank will mess up, prefixes won't work and commands won't work at all. I can then just as easily set them back to default rank and it will all work again.
This issue has been very problematic with one issue resolve turning into a much larger issue.
Please help, thank you.
PERMISSIONS:
http://pastebin.com/2VTa3ebZ

Ugh someone please help me? Thanks :/

EDIT by Moderator: merged posts, please use the edit button instead of double posting.