Ruby on Rails, How to set a group of attributes unique for another class

sorry for the unintelligible title but I didn't know how to explain the problem :D My project consists in building a rail transport site, so I have to write some routes, stops, trains and so on.. I want to know how I can click on the route and see just its own stops. Now I can see only all stops in general. I know I'm very confusing, but I hope you can help..thanks