FROM TONGA TO THE CHARTS : THE JETS: A SQUEAKY-CLEAN TEEN TEAM

Another sibling pop act. Sweet, but old hat, right?

Not in the case of the Minneapolis-based Jets, who play two shows tonight at the Roxy. For one thing, the eight young Wolfgramms have five more potential band members at home with Mom (and yet another on the way). They also happen to be as adept at Polynesian dancing as they are at bouncy pop stage moves, thanks to years of training by their Tongan parents, who moved to the States from the South Pacific island chain in 1965.

The five brothers and three sisters, ages 12 to 20, have already made a mark with their effervescent, harmonically rich debut album “The Jets,” which spawned the big dance hit “Curiosity.” That song and the new single, “Crush on You,” are performed by Elizabeth in a sophisticated, controlled voice that belies her age; she’s only 13. Indeed, she and LeRoy (20), Eddie (19), Eugene (18), Haini (17), Rudy (16), Kathy (15) and Moana (12) are all strikingly attractive and look and act years beyond their ages.

Which is not to say they’re lacking in youthful enthusiasm. Over chili and cheeseburgers in an Anaheim hotel coffee shop the band members had a grand time zinging one-liners at one another as they exuberantly explained what the Jets are all about.

“We’re squeaky clean--no caffeine!” said LeRoy, the group’s unofficial spokesman. In a way, his joke isn’t far from the truth.

The themes of dedication and teamwork kept cropping up during the retelling of the band’s history. Until the mid-’70s, the family toured throughout the United States and Canada as a Polynesian dance revue (“fire-eating and everything”), supplementing their income with part-time yard work. Eventually, LeRoy started developing other musical talents.

“Mom and Dad finally got sick of me pounding on pots and pans and bought me a drum kit,” he recalled. “I learned to play it from listening to the radio. We had a family meeting in 1978 and Dad said, ‘What’s it going to be--yard work or music full time?’ So we voted for music. Some of the other kids learned instruments and Mom was our singer. We’d play weddings and Tongan dances, doing half Polynesian music and half Top 40.”

In the early ‘80s, their mother, Maikeli, bowed out of the act to devote more time to the kids at home in Minneapolis, where they finally settled. She also began to create the group’s trademark bright, funky costumes--”a high-school-hip street look, like the Jets in ‘West Side Story,’ ” LeRoy explained.

Meanwhile, the older children passed on musical know-how to the younger ones, and all eight now sing and are multi-instrumental. They eventually decided to concentrate exclusively on pop. “That happened after this chain of Hawaiian hotels we were hired to play at went bankrupt,” LeRoy recalled. “There we were, standing outside in the freezing cold in our grass skirts. That’s when we decided there wasn’t a huge future in Polynesian dance.”

The Jets honed their pop act under the watchful eye of their father, Mike, and eventually landed a manager and a record deal. “It’s not like we’ve been this overnight success,” LeRoy noted. “We’ve paid the dues and are still paying them. Dad and all of us planned this and worked for it since 1978. Back then Dad couldn’t speak English very well, so he’d simply say over and over again ‘Just do the thing right!’ ”

Doesn’t all this constant togetherness get on everyone’s nerves? “Oh, sure. We’re not perfect or anything,” LeRoy said. “We have our arguments like every other family. But we work really hard at getting along. That’s why we meet every week to talk about things and work the grudges out.

“You know, most families eventually split up and go their separate ways. But Dad always wanted us to stay together in a unit, whatever business we ended up doing. And that’s what we’ve done.”

As choreographer Rudy put the Jets through their paces in the hotel disco after lunch, the giggles and grins suggested that these brothers and sisters genuinely enjoy one another’s company. “OK, on the count of three I want us all to jump in the air, together ,” he commanded. And they did, in perfect sync, wild tennis shoes glittering under the spotlights.