JPA unidirectional @ManyToOne relationship remove childs if parent is removed

Question

I have a class A and classes B and C:

public class A {
    @Id
    protected String name;
    ...
}

public class B {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @NotNull
    @ManyToOne
    private A a;
    ....
}

public class C {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @NotNull
    @ManyToOne
    private A a;
    ....
}

If A entity is removed, I want all child entities to be removed too. I dont want a bidirectional relationship (in order to no have cycles between the classes and in order to not add more attributes to class A). Is that possible using Hibernate or have I to do this programatically in my service class?.

I guess if bidirectional relationship is needed for this I can write a parent class for B and C and use this parent class in a list to reference the childs in class A?