I would base this decision on
How much time will it take start to finish for you?
How many participants?
What level of training will you be doing?
Do they all have the same fitness goals?
Are you teaching a specific task to enhance performance?
What do you charge for group training?
Can you offer an incentive: 5 classes for $100 10 for $185? per person?
Hockey players are generally really fit under all of that gear!!
I have worked with teams at various levels of competition and I think that this is definitely another important factor that needs to go into the equation. The level of competition is directly related, in my opinion, to the level of detail and preparation that you may have to have, and therefore, may definitely effect your rate. Are you training beginner/kids or semi-professional/elite players. When doing your other computations, please take this into account as well.