Complex sentence: This is followed by Groucho who wisecracks his way through his unsolicited audition, and, finally, Harpo bursts in, who pantomimes his way through his take on the audition.
Split into simpler sentences: This is followed by Groucho, who wisecracks his way through his unsolicited audition. Finally, Harpo bursts in, who pantomimes his way through his take on the audition.