Did you hear about the seven-sibling Scandinavian folk dance troupe that ran out of money in the middle of a tour of the South Pacific? They settled in Tonga, dropped their reindeer sweaters and yodel music in exchange for a Top 40 act and became international pop stars. Even after they earned enough money to live anywhere they wanted, they decided they liked the South Seas, so they bought a big house on an island and lived there happily ever after with their mother, father, and eight other brothers and sisters.

Sound far-fetched? It's no less believable than what really happened to the Jets.

The seven singing Wolfgramm brothers and sister from Anoka, Minn., better known to millions of pop music fans around the world as the Jets, have lived a grass-skirt-to-riches story that would stretch even a record company publicist's ability to exaggerate.In 1976, having moved to Salt Lake City from one of the 150 islands of Tonga, they hit the road with their mother as a hula-hula act called the Polynesian Pearls. Last Friday they performed hits from their latest gold record at President George Bush's inaugural Youth Ball in Washington, D.C.

In 1982, having run out of gigs and money in Minneapolis, they formed a Top 40 bar band called Quasar and began pleading with a local manager to come see their act. Next month, they'll be in Los Angeles in hopes of winning a Grammy award for the best rhythm-and-blues vocal by a duo or group.

The Jets have come a long, long way in 12 years, but they're not going any farther. They say they're staying right here.

They could go back to Salt Lake City, bulwark of the Mormon Church, whose missionary work brought them to this country in the first place, or they could relocate in Los Angeles, hub of America's music business. But the Jets have decided that they can be superstars just as easily - and perhaps more comfortably - in Minnesota.

For example, 16-year-old Liz Wolfgramm has plans for a solo career someday, but she's not going to let that sever her new-found roots.

"I'll be here all my life," Liz said in a recent group interview with her brothers, Leroy, 23, Eddie, 22, Haini, 20, and Rudy, 19, and sisters, Kathi, 18, and Moana, 15.

The Wolfgramms recently bought a large house on 10 acres of land near Anoka. The Jets have begun recording their third album at Paisley Park Studios in Chanhassen, Minn., and there are plans for a network television pilot to be made this spring, also at Paisley Park. In their spare time, the Jets shop at the malls, go to movies and hockey games, root for the Vikings and Twins (They sang at half time of the recent Rams-Vikings wild-card game and performed the national anthem before the seventh game of the 1987 World Series.) And they love the change of seasons.

In other words, Mike and Vake Wolfgramm and their 15 children - that's right, eight boys and seven girls, ages 1 to 23 - now call Minnesota home, even though their arrival here was a complete fluke.

In 1965, Mike Wolfgramm - whose great-great-grandfather was a German merchant seaman - moved to the United States from the British protectorate of Tonga with his wife, their 1-year-old son, Leroy, and Mike's father. They started out in San Francisco but moved to Salt Lake City, where a large number of Tongans reside (the Mormons have proselytized in the South Pacific since before the turn of the century).

Reminiscent of the Osmond family - another prolific Mormon entertainment dynasty - Vake (pronounced Va-KAY) and Mike Wolfgramm began having more children. And, as a singer and dancer herself, Vake began to pass on her entertainment skills to her growing family.

The Jets are a logical extension of their hard-working father and talented mother. While Vake Wolfgramm taught the kids to sing and dance, Mike Wolfgramm held down the jobs that allowed them to develop their act, and later he drove the group around the hotel circuit as the Polynesian Pearls.

"Dad had a really good job when we were in Salt Lake, working as foreman of a Safeway milk department for $15 an hour," Leroy recalls. "But it just came to the point where we had to make one decision or the other - do this full time, 100 percent, or just do it part time. My dad decided to let us just concentrate on this, so he quit his job."

The sacrifice paid off. Mike also advised his kids to learn American pop music while they were doing their hula show - and that paid off, too.

"We had a lot of things going for us motivation-wise, including our customs, as far as being a new immigrant family from the islands," Leroy says. "Our parents were literally first-generation. Coming with that kind of mentality helped us to go forward with the motivation it takes to look for a career and make it."

That persistence led them to one of the premier pop-group managers in Minnesota. Don Powell had been a singer, producer, arranger and personal manager for such stars as Stevie Wonder before quitting the music business in 1975 to concentrate on selling cars at his Ford dealership.

He had no intention of returning to managing, but that was before a determined family of Tongans finally prevailed upon him to catch their act at the Sheraton Northwest in Brooklyn Center, Minn.

Now Powell manages the Jets, Boys Club (featuring the Wolfgramms' adopted brother Eugene, who'd been in the group off and on since the inception of the Polynesian Pearls) and a new Warner Bros. heavy metal band called Powermad - all from his office suite in the warehouse district just north of downtown Minneapolis.

"They kept calling me," Powell recalls of the campaign to get him to go see the Jets (then Quasar). "They finally got me in a moment when I couldn't say no."

So, because Powell chooses to live and work here, and because he was able to take a talented but inexperienced family band and turn its members into teen idols, the Jets have made their peace with Minnesota's subzero winters and road construction summers.

"I love the fall," Liz says.

"I love the lakes," says Leroy.

"I went water-skiing a couple of years ago and practically drank half the lake trying to get up," says Haini.

"I'm going ice fishing one of these days," says Eddie.

"Like all Minnesotans, you might think it's kind of weird to live here sometimes, but you just love it," Liz says.

The Wolfgramm family has certainly sampled a sizable portion of the Twin Cities. When the hotel chain they were performing for went bankrupt in 1982, the hotel owners put the family up in their own home in St. Anthony for two months. Since then, they have rented a succession of houses in Brooklyn Park, Wayzata, New Hope, Minnetonka and Maple Grove before buying their first house on a quiet road outside Anoka.

"After the last tour, we had enough money to buy a house," Leroy says. "There are a few more kids coming, because Mom had a few more babies."

Two of the younger Wolfgramms, aged 13 and 12, are candidates to join the group some day. The other five are too young to think that far ahead.

"By the time they get to be our age, we'll probably be too old," Liz says.

Elizabeth and Moana are the only two Jets still receiving high school tutoring; the younger Wolfgramm kids all go to school in the Anoka area. Mom and Dad manage to keep the whole family together by scheduling family meetings that include all 15 kids.