Bonnie Hammer

FORTUNE — The Fortune Most Powerful Women list includes, among its 50 execs, three stars at NBC Universal. The most powerful of the trio has just gained more ground.

NBCU’s announcement yesterday that Bonnie Hammer, No. 33 on Fortune‘s power list, is now in charge of all of the company’s cable entertainment channels is not such a great surprise. Hammer reprogrammed and built USA Network and Syfy into two of the most lucrative properties in the cable business–while generating some $2 billion in annual profits for NBCU. But more than that, since Comcast took over NBCU from General Electric two years ago, Hammer, 62, has proven herself to be not only a highly effective change agent (her latest overhaul: E!) but a strong manager who attracts talent on and off the screen. In his letter to employees, NBCU CEO Steve Burke called Hammer a “natural business leader.”

While Burke is labeling Lauren Zalaznick’s new EVP job a “promotion,” it’s really not that so much as an elegant way to keep two key executives in his stable. Zalaznick, No. 48 on the Fortune MPW list, is ceding control of two major networks, Oxygen and Bravo, to Hammer. Bravo is the onetime niche channel that Zalaznick refashioned into a red-hot, high-margin network for affluent viewers. Now without any significant P&L oversight, Zalaznick, 50, is directing digital strategy and more across NBCU. Given that she is the company’s quirky, creative culture czar (her office looks like a colorful pop-culture museum display) and Internet champion, she has a gig that seems fitting. Now it is her job to make the role critical to Burke’s plan to expand the company.

While Hammer and Zalaznick (who, coincidentally, both grew up on Long Island, the youngest of three children) grab the spotlight, the other NBCU exec on the MPW list, News Group chairman Pat Fili-Krushel (No. 41), wields her power more quietly. Fili-Krushel (also from Long Island, the eldest of three kids) was on our first MPW list in 1998, when she was named to head ABC. Ever since, she has spent her career advising Walt Disney CEO Bob Iger and then Time Warner’s Jeff Bewkes behind closed C-suite doors. As one of Burke’s key advisers, she’s now more powerful than ever.

And with Steve Capus’ recent exit as the boss at NBC News, Fili-Krushel, 59, is in charge of finding his successor. In the running for that big job: another NBCU woman, Alex Wallace.