Do you mean as beginner, intermediate, and expert?
There are a lot of different types of riders based on terrain, experience, fearlessness, sighters, etc.
For example, I consider myself a well experienced rider and like going to the mountains, but I'm not one of those guys that will drop/jump 20' (or more) off a cornice. In fact, I don't even care to go down mediocre steep mountains, but do because I like the view from the top of the mountains.
So how do you break people into groups?
1 - riding experience, usually 1st timers, novice, intermediate, expert, and Pro.
2 - speed: some people don't like to do more than 40 MPH, even in places like lakes.
3 - terrain: hard pack trail, deep snow, large hills and mountains.
4 - Distance: Not everyone can stay out 8 hours or more at a time. Some people just want to ride for a couple hours.
5 - Type of sled(s): A 340cc short track is going to have a tough time in the deep snow or mountains, and you really don't want to run 2" paddle tracks on hard pack snow or ice for long periods of time.
Now there are definitely people that cross over and there are definitely ways to combine all of this.