Combining observables in RxJava, is there a better way to do this?

I'm learning RxJava. I'm retrieving film information from two API.

• The first API (Api1 class) receives an id and returns a JSON (Api1Dto class):

{ id : "123456", title : "Top Secret", api2Id : "7787" }

• The second API (Api2 class) receives an api2id and returns a JSON (Api2Dto class):

{api2Id : "58582", "director" : "Peter Jackson" }

I want, from an id, compose a structure with all those fields (Film class):

{ id: "123456", title : "Muahaha", api2Id : "5552", director : "Uncle Joe" }

I have this code:

 public Observable<Film> getById(final String id) { return api1.getById(id).map(new Func1<Api1Dto, Film>() { @Override public Film call(Api1Dto dto1) { Film film = new Film(); film.id = dto1.id; film.title = dto1.title; film.api2Id = dto1.api2Id; return film; } }).flatMap(new Func1<Film, Observable<Film>>() { @Override public Observable<Film> call(final Film film) { return api2.getById(film.api2Id).map(new Func1<Api2Dto, Film>() { @Override public Film call(Api2Dto dto2) { film.director = dto2.director; return film; } }); } }); } 

It works, but I wonder if this is the correct way to do it or exists a better/more elegant solution using functions that RxJava provides.