Redmine

Hi,
I need to make a redmine plugin handling patients for our project. It needs to handle patients and for a given patient his appointments and therapies.
Now, should I push everything in a single controller or should there be 3 controllers for this. Because I wonder how to handle project_menu navigation buttons. Button Pacient should be active for all 3 controllers.
Any hint on good practice is appreciated.

Best regards, Zdravko