Transform querydsl query in nested class

I have 3 entities

public class Student {
  private Long id;
  private String name;
  private String gender;
  private Integer age;
  private List<Subject> subjects;
}

public class Subject {
  private Long id;
  private String description; 
  private List<Grade> grades;
}

public class Grade {
  private Long id;
  private BigDecimal value;
}

I want to generate a DTO like this:

public class StudentTransient {
  private Long studentId;
  private String name;
  private List<SubjectTansient> subjects;
}

public class SubjectTansient {
  private Long subjectId;
  private List<BigDecimal> grades;
}

So in Grade class, I just wanne get the grades and group then by subject, as I want to group subjects by student.

How can I do this?

I dindt found a example like this, I used transform and GroupBy.groupBy but no achived my goal.