To prepare, they read some books on scriptwriting and watched a how-to DVD from Syd Field, a screenwriting guru. Their script changed substantially from the first table read in 2007 to the shoot. The director, Paul Feig, had the cast do the scenes as written and then improvise, while Ms. Wiig and Ms. Mumolo handed him notes as they punched up their own material — a trial for anybody but seasoned comedians, and not typical for Oscar contenders. Since 2000, only 11 screenplays that credit women as writers or co-writers have been nominated, and only two of those — “My Big Fat Greek Wedding” and “Bridesmaids” — are true comedies.

Ms. Mumolo, who appears briefly in the movie as Ms. Wiig’s nervous seatmate on a plane, was also eight months pregnant during the shoot. “Seventeen hours a day — it was a challenge, I’ll just say that,” she said.

More Groundlings — Jim Rash and Nat Faxon — are represented in “The Descendants,” also written by the director, Alexander Payne. Jim Burke, a producer of “The Descendants,” asked Mr. Rash and Mr. Faxon to adapt Kaui Hart Hemming’s novel of the same title, whose rights he had bought even before publication, because he liked the Hawaiian setting.

But the book is written in the first person, with interior monologues from the point of view of Matt King (George Clooney). Getting out of that perspective “was certainly a challenge,” Mr. Faxon said, “because you wanted to understand this character, and in the book it was so well described, because he could tell you exactly how he was feeling.” The solution came from Mr. Payne: an opening voice-over that gives the background.

Mr. Payne, the writer-director of “Sideways,” for which he won a screenplay Oscar, schooled Mr. Rash and Mr. Faxon (also an actor in movies like “Zookeeper” and “Bad Teacher”) on how to balance comedy and emotion.

“I think that was something that was very beneficial for us to watch,” said Mr. Rash, who plays the college dean on the TV series “Community.” “Applying his tone, and watching him work, not only in the writing but as a director.”