Who's a beginner?
Someone who has tried that specific discipline in a group before but has not mastered all the skills required to be on level and in slot all the time.
Who are intermediate?
Someone who has mastered the necessary skills to be in a group on level and in slot all the time, so can start to push towards more transitions and complex dive plans.
Who are advanced?
Any size group, On level, in Slot all the time, able to remember and successfully execute complicated dive plans as part of a team.