Complex sentence: Among the two of them, Jayalakshmi had rendered only a few songs in films and most of it would be duets with Rajalakshmi, whereas Rajalakshmi had more chance as a playback singer in films.
Split into simpler sentences: Among the two of them, Jayalakshmi had rendered only a few songs in films and most of it would be duets with Rajalakshmi. Whereas Rajalakshmi had more chance as a playback singer in films.