ManyToAny

@ManyToAny(
            metaColumn = @Column( name = "tipo_destinatario" ))
    @AnyMetaDef( 
        idType = "integer", 
        metaType = "string",
        metaValues = {
    			@MetaValue(value = "A", targetEntity = Aluno.class),
    			@MetaValue(value = "P", targetEntity = Professor.class),
    			@MetaValue(value = "F", targetEntity = Funcionario.class) })
    @Cascade( { org.hibernate.annotations.CascadeType.ALL } )
    @JoinTable( name = "mensagens_destinatarios", joinColumns = @JoinColumn( name = "mensagem_codigo" ),
            inverseJoinColumns = @JoinColumn( name = "codigo_destinatario" ) )
	private List<Autenticavel> destinatarios;