JPA - OneToMany - Non Primary Keys?

Question

I've inherited a db that I'm slowly trying to fix up, I ran into an issue with relationship between two tables that looks like this:

public class MyTable {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "id", nullable = false, unique = true)
    private Long id;
    
    @Column(nullable = false, unique = true)
    private String myTableId;
}

public class OtherTable {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    @Column(name = "id", nullable = false, unique = true)
    private Long id;
    
    @Column(nullable = false, unique = true)
    private String otherTableId;
    
    @OneToMany
    private List<MyTable> myTables;
}

The problem is that the OneToMany maps on the wrong ids. The @Id columns instead of myTableId and otherTableId. I sadly can't change the @Id columns without breaking a lot of functions so I need to create the relationship between the two tables on their non primary keys; myTableId and otherTableId.

I've searched up and down but never found a solution that does it correctly. I tried adding @JoinColumn to the myTables column but then it only found matches where myTableId = otherTableId instead of all otherTableId that myTableId owns. What am I doing wrong and how do I fix this relationship so it acts correctly?