EpisodePerson.java

@Entity(...)
class EpisodePerson {

  @EmbeddedId
  Id id;
  @Enumerated
  EpisodeRole episodeRole;

  Episode getEpisode() {
    return getId().getEpisode();
  }
  
  @Embeddable
  class Id {
    @ManyToOne
    Episode episode;
    @ManyToOne
    Person person;
  }
}