How do I create an entity with multiple parent entities using Hibernate reactive?

Question

I'm trying to create a data model using hibernate reactive where one entity owns two other entities and each of those two entities have a one-to-many relationship with a fourth entity. Here is an example of how the tables would be set up:

@Entity
@Table(name = "OBJECT_A")
public class ObjectA {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    public Long id;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JoinColumn(name = "OBJECT_A_ID")
    public Set<ObjectB> objectBs;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JoinColumn(name = "OBJECT_A_ID")
    public Set<ObjectC> objectCs;

}

@Entity
@Table(name = "OBJECT_B")
public class ObjectB {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    public Long id;

    @OneToMany(mappedBy = "objectB", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Set<ObjectD> objectDs;

}

@Entity
@Table(name = "OBJECT_C")
public class ObjectC {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    public Long id;

    @NotBlank
    @Column(name = "NAME")
    public String name;

    @OneToMany(mappedBy = "objectC", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Set<ObjectD> objectDs;

}

@Entity
@Table(name = "OBJECT_D")
public class ObjectD {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    public Long id;

    @ManyToOne
    @JoinColumn(name = "OBJECT_B_ID", nullable = false)
    public ObjectB objectB;

    @ManyToOne
    @JoinColumn(name = "OBJECT_C_ID", nullable = false)
    public ObjectC objectC;

}

I think this table structure works fine. I just can't figure out how to actually persist data following this model into the database. Normally, I would just get an ObjectA from the API layer and call session.persist on that, and due to everything being CascadeType.ALL it would just persist all of the child objects. The problem I'm having is that with a JSON Rest API you can't really represent the idea of an ObjectD having two different parent objects. In the JSON structure, ObjectD is a child of ObjectB and then I have a reference back to ObjectC as a part of ObjectD. Here is an example of an objectA in JSON:

{
    "objectBs": [
        {
            "objectDs": [
                {
                    "objectC": {
                        "name": "example_name"
                    }
                }
            ]
        }
    ],
    "objectCs": [
        {
            "name": "example_name"
        }
    ]
}

As you can see, the ObjectC in the top level objectCs list and the one that is a part of the ObjectD are really the same object. How would I persist the JSON representation above into the database using hibernate? I appreciate any help. Sorry if this contrived example is a little hard to follow.