Hello,
i'm new to k2, and i'm building a managing system for a small gym center.

There will be only 1 real user (secretary) that will insert the courses, the members, and the trainers. The secretary has to relate those data, because every course has 1 or 2 trainers and some members. So, if the secretary will click on the name of a course (for example... YOGA CLASS) , she will have the possibility of including trainers and members at that courses.

The best idea should be to use K2 items as courses, and make some extra fields for them (timetables, notes, ecc...) but the problem is: how can i relate the members and the trainer to the courses?
I have a list of courses (items), and i have a list of members and trainers (users): for every course there must be a list of users, and for every user there must be a list of the courses where he's subscribed.
How can i do that?
Another solution is that the members are not users but are different kind of items, but i still have the same problem. I have to relate one course item to many members items.
How can i do that?

Thank you very much