A Brilliant Hatchet Job and a Bunch of Hacks : CBS: Barbara Hershey’s portrayal of a killer was inspired. Cross-promotion by the network-owned station’s newscasters wasn’t.

As a rule, good dramatic roles for women in TV movies each season can be counted on one finger.

The present season has been a happy exception, however, leading to some simply outstanding performances. Christine Lahti’s middle-class transient mother in “No Place Like Home” immediately comes to mind, as does Lesley Ann Warren’s hapless matriarch in “Family of Spies.”

More recent was that splendid piece of acting by Barbara Hershey in Tuesday’s swell sleeper of a movie on CBS, “Killing in a Small Town.” Hershey demonstrated again what a fine actress she is as Candace Montgomery (renamed Morrison for the movie), the seemingly meek Texas homemaker and church choir member tried for murder 10 years ago in the ax slaying of another woman. Although admitting she whacked her friend 41 times, Montgomery was acquitted when her lawyer was able to persuade a jury that she swung the ax in self-defense and that her grisly overreaction was an explosion of intense emotion she had been holding in since childhood.

What control and discipline by Hershey. Her suppressed rage was something to behold. So were those times she totally surrendered herself to her subject’s latent violent side, first exposed through hypnosis and later in a defense of life so frenzied that she turned the weapon on her attacker and hacked the woman into a bloody mess. Hershey’s great accomplishment was to evoke feelings of both horror and sympathy.

Bring out the Emmy.

But not for KCBS Channel 2, which--this still being ratings sweeps--interviewed Hershey for its 11 p.m. newscast following the movie, once again hoping to attach one of its news programs to the coattails of a CBS entertainment program.

Channel 2 didn’t even get it right. Leading into the Hershey interview, anchorman Jim Lampley said that the actress would disclose how she got “into the mind of a murderer.” Uh . . . what “murderer”? In the eyes of the law and the jury that acquitted her, Montgomery was not a murderer.

Lampley also said in his introduction that Hershey would explain how “that murderous instinct may be inside all of us.” What “murderous instinct”? Self-defense, remember? Not murder. In fact, Hershey mentioned nothing about a “murderous instinct,” only that a “dark side” may exist in all of us.

It surely does in Channel 2 and in its network-owned competitors, KABC-TV Channel 7 and KNBC Channel 4, evidenced by their continued--and now even intensified--interweaving of news and entertainment programs to hype sweeps ratings.

For ages now, stations have been manufacturing news stories to be used in conjunction with entertainment programs, the purpose being to use each to promote the other. Night after night it happens. What better evidence of news serving entertainment, of news programs being tailored to fit entertainment programs?

As Channel 2 was hitching its 11 p.m. news to “Killing in a Small Town,” for example, Channel 4 was airing a story on its 11 p.m. news tied to that night’s NBC movie “Last Flight Out.”

On and on it goes, involving network news, too:

* It’s May 7. Channel 2 ties its 11 p.m. news to that night’s CBS News special, “Face to Face With Connie Chung,” by doing a feature on Chung.

* It’s May 14. Chung, promoting her second “Face to Face” special, is a guest on the syndicated Joan Rivers talk show carried on Channel 2. In a double whammy, the clip that CBS gives the Rivers program not only advertises that night’s Chung special, but also shows her interviewing Dixie Carter, one of the stars of “Designing Women,” the CBS series preceding the Chung special. This is a CBS festival.

* It’s Wednesday. On its 5 p.m. news segment, Channel 2 features an “exclusive” interview--as if any one else would want it--of Geraldo Rivera, whose syndicated talk show precedes the 5 p.m. news. (This is reminiscent of Channel 7’s “exclusive” interviews of Oprah Winfrey, whose talk show leads into the station’s 4 p.m. newscast.)

On its 11 p.m. newscast, Channel 2 features an interview of Rivers tied to the preceding CBS movie starring Rivers.

By what ethical standard can all of this be justified?

Apparently the same standard that guided Channel 2 on Mother’s Day, when anchorwoman Bree Walker ended the 6 p.m. Sunday newscast by chatting on the phone with her mother.

This two-minute extravaganza featured Walker and her co-anchor/husband Lampley exchanging love greetings on the air with Walker’s mother. Lampley: “I can call her ‘Mom,’ too, now, because’s she’s my mother-in-law.”

Before this penetrating mini-documentary had ended, Walker’s mother had told her daughter how proud she was of her and had heard Walker and Lampley each reciprocate with: “I love you, Mom.”

And this is the city’s hard news station?

The KCBS news department crows and crows about its investigative stories on wrongdoing. Has it considered investigating itself?

The practice of tainted cross-promotion is also exemplified by Channel 7 sportscaster Todd Donoho’s series this week highlighting radio personalities Mark & Brian. It just so happens that their morning show on ABC-owned KLOS-FM features Donoho as a regular.

Donoho is on a roll, the Mark & Brian spectacle following his triumphant investigative reporting on skimpy bathing suits--with the women in them.

He enunciates poorly, running his words together. His editorials may be brilliant, but who can tell?

No matter. This is one Channel 2 employee who won’t get thrown off the air for being unable to communicate. That’s because the man who delivers the editorials on Channel 2 is the station manager.

“I’m Bob Hyland” is his sign-off, about the only thing he says that you can understand.