Question (PEX) Rank Priority not working?

So, if a player has multiple ranks, such as Immortal (a donator rank), and Trainee-Moderator, I want the prefix of Trainee-Moderator to trump the Immortal one, and show up in chat instead of Immortal. I thought this could be accomplished with ranks and rank ladders, but that hasn't worked either!

Code:

groups:
  default:
    options:
      default: true
      rank: '1000'
      rank-ladder: user
    permissions:
    - modifyworld.*
    - essentials.spawn
    - essentials.msg
    - essentials.afk
    - essentials.help
    - essentials.helpop
    - essentials.tpa
    - essentials.tpaccept
    - essentials.tpahere
    - essentials.tpadeny
    - essentials.tptoggle
    - essentials.home
    - essentials.sethome
    - essentials.sethome.multiple.default
    - essentials.sethome.multiple
    - auction.start
    - auction.bid
    - essentials.kit
    - essentials.kits.starter
    - essentials.kits.food
    - silkspawners.place.*
  knight:
    options:
      rank: '950'
      rank-ladder: donator
    inheritance:
    - default
    permissions:
    - essentials.kit.knight
    - essentials.sethome.multiple.knight
    - silkspawners.silkdrop.*
    - essentials.seen
    - essentials.seen.banreason
  hero:
    options:
      rank: '900'
      rank-ladder: donator
    inheritance:
    - knight
    permissions:
    - essentials.kit.hero
    - essentials.sethome.multiple.hero
   
  veteran:
    options:
      rank: '850'
      rank-ladder: donator
    inheritance:
    - hero
    permissions:
    - essentials.kit.veteran
    - essentials.sethome.multiple.veteran
    - essentials.back
    - essentials.back.ondeath
   
  elite:
    options:
      rank: '800'
      rank-ladder: donator
    inheritance:
    - veteran
    permissions:
    - essentials.kit.elite
    - essentials.sethome.multiple.elite
    - essentials.chat.color
   
  champion:
    options:
      rank: '750'
      rank-ladder: donator
    inheritance:
    - elite
    permissions:
    - essentials.kit.champion
    - essentials.sethome.multiple.champion
    - essentials.feed
   
  legend:
    options:
      rank: '700'
      rank-ladder: donator
    inheritance:
    - champion
    permissions:
    - essentials.kit.legend
    - essentials.sethome.multiple.legend
   
  titan:
    options:
      rank: '650'
      rank-ladder: donator
    inheritance:
    - legend
    permissions:
    - essentials.kit.titan
    - essentials.sethome.multiple.titan
    - essentials.repair
   
  mystic:
    options:
      rank: '600'
      rank-ladder: donator
    inheritance:
    - titan
    permissions:
    - essentials.kit.mystic
    - essentials.sethome.multiple.mystic
    - nv.use
   
  immortal:
    options:
      rank: '550'
      rank-ladder: donator
    inheritance:
    - titan
    permissions:
    - essentials.kit.immortal
    - essentials.sethome.multiple.immortal
  trainee:
    options:
      rank: '500'
      rank-ladder: staff
    inheritance:
    - default
    prefix: '&5[Trainee-Mod&7] &6'
    permissions:
    - essentials.kick
    - essentials.kick.notify
    - essentials.chat.color
    - essentials.chat.url
    - essentials.tempban
    - essentials.tempban.notify
    - essentials.mute
    - essentials.mute.notify
    - essentials.seen
    - essentials.seen.banreason
    - warnings.warn
    - warnings.viewall
   
  mod:
    options:
      rank: '400'
      rank-ladder: staff
    inheritance:
    - trainee
    permissions:
    - chat.mod
    - essentials.ban
    - essentials.ban.notify
    - essentials.invsee.preventmodify
    - essentials.enderchest.others
    - clear.chat
  admin:
    options:
      rank: '100'
      rank-ladder: staff
    permissions:
    - '*'
    - - permissions.*
    - chat.admin
   
schema-version: 1
users:
  cd402a94-2bab-3c7d-b351-f8b59162989b:
    group:
    - admin
    options:
      name: Iwan
  7129e1f7-437a-443c-aa52-11cbd8390639:
    options:
      name: Iwan
      last-login-time: '1435110178'
      last-logout-time: '1435109996'
    group:
    - admin
  80a12e7f-f888-4221-bc3e-725145095133:
    group:
    - immortal
    - trainee
    options:
      name: iwantafez
      last-login-time: '1435102582'
      last-logout-time: '1435103412'
  96a2ab0a-daef-43cc-bc35-47c3e292bed0:
    group: []
    options:
      name: a_boy_guy
      last-login-time: '1435022568'
      last-logout-time: '1435023319'
  6f5215b1-9d6f-4dc5-aa25-4d93ad6ba222:
    group: []
    options:
      name: lukesheep
      last-login-time: '1435029125'
      last-logout-time: '1435109125'
    permissions:
    - trail.magic

 

There shouldn't be any space lines between one group and another