Hibernate : Fetching data based on multiple table data status

Question

@Entity
@Table(name = "service_staff")
public class ServiceStaff implements Serializable {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "id")
  private long id;

  @JoinColumn(name = "service_id", referencedColumnName = "id", nullable = false)
  @OneToOne(optional = false)
  private Service serviceId;

  @JoinColumn(name = "user_id", referencedColumnName = "id", nullable = true)
  @OneToOne(optional = true)
  private User userId;

  @JoinColumn(name = "designation_id", referencedColumnName = "id", nullable = true)
  @OneToOne(optional = true)
  private Designation designationId;

  @Column(name="head")
  private boolean head;

  @Column(name="head_type")
  private int headType;

  .......
  
}

  @Entity
  @Table(name = "project_staff")
  public class ProjectStaff implements Serializable {

      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      @Column(name = "id")
      private long id;

      @JoinColumn(name = "project_id", referencedColumnName = "id", nullable = false)
      @OneToOne(optional = false)
      private Project projectId;

      @JoinColumn(name = "user_id", referencedColumnName = "id", nullable = true)
      @OneToOne(optional = true)
      private User userId;

      @JoinColumn(name = "designation_id", referencedColumnName = "id", nullable = true)
      @OneToOne(optional = true)
      private Designation designationId;

      @Column(name="head")
      private boolean head;

      @Column(name="head_type")
      private int headType;

      .......
      
  }

Above are some of the data tables on my project where I want to find the remaining list of data from 'ServiceStaff' model class which are not exist on ProjectStaff class. Here in ServiceStaff data the staff may be of type User/Designation/Head where Designation & Head has a headType with value 1 for 'Main' and value 2 for 'Assistant'.How can I fetch the result as below using Hibernate with minimum load in my java code. Do I need to use any join to make it easy? Please excuse for the way I described it here since, I didn't find any other way to explain it.

Result I wanted is as below :

Explanation for this result is as below :