How to set/show cross relations?

[AndreyChursin]

I have a list of courses on Bolt and I need add trainer for them

courses: 
  relations:
          trainers:
              ....
          
trainers:
      ....
      

But on the trainer's page I can't see all the courses in which it was used!
should I add relation field for trainers and add all courses there(?):

trainers:
    relations:
        courses: 
        ....