Workers at the post office on Hadley Street in Midtown have gotten used to seeing three women running around the block in high heels. “They know us now. They wave,” says Bunni Ray, one third of hip-hop trio Blushhh Music. It’s all part of the program developed by Mathew Knowles, musical creator of Destiny’s Child and genetic creator of Beyoncé and Solange.

Beyoncé has spoken about the intense regime her father put her through en route to becoming a superstar. Today, Knowles isn’t about to mess with his formula for success. “Nothing has changed—it’s fitness, conditioning, vocal lessons, choreography, putting the music together, and then at that point, putting your performance together and learning how to not be a singer but an entertainer. It’s a huge difference, a singer or a rapper versus an entertainer. Nobody is born with it. It has to be developed,” he explains, chatting in a simple white tee and jeans in the Midtown headquarters of his record label, Music World Entertainment, with platinum records lining the walls.

Knowles carries himself like a tough football coach, one whose expertise is backed up with stats at the ready. Introducing Blushhh Music at their shows, he’s been known to refuse to speak until everyone is completely silent. The girls seem to have a tight, supportive relationship with their mentor, but they always refer to him as Mr. Knowles.

Music World includes a stable of musical acts ranging from gospel to Tejano to country, but Knowles likes to say his specialty is girl groups. He not only managed Destiny’s Child, the second bestselling such group of all time, but also popular gospel trio Trin-I-Tee 5:7. He’s betting on Blushhh Music to have the same success in the hip-hop realm.

Rapper and California transplant Sunni started the group at 15, in 2009, cycling through a few members before finding Tali, a big-haired, honey-voiced vocal powerhouse, on Facebook, under the name “TALI BEST SINGER.” They added a third member and set about getting any gigs they could find, lining up for hours for their chance to compete in underground rap battle showcases at Warehouse Live.

Five years later, Knowles met the group, started advising them and, eventually, signed them. After another lineup change—the life of a girl group never did run smooth—a year ago Sunni and Tali found Bunni Ray, with her piercing, Left Eye–style rhymes, on Instagram, and the three got to work.

At Knowles’s direction, the girls lost a collective 75 pounds—“we’re in a pretty person’s business, I didn’t make the rules,” he says—and began to craft their look, image and sound in earnest. Sunni is “swaggy,” Knowles explains, while Tali is the free spirit and Bunni Ray, the sultry one. Their style is a little sporty and a little street, with a healthy dose of sex appeal.

In June, the women dropped their first single, “Old School Back,” which samples a Lil’ Kim track and introduces their throwback sound. “It was something I always wanted to do with Destiny’s Child,” says Knowles, “to take older songs and re-do them with new vocals, new melodies and new lyrics.”

The months since then have been a day-to-day hustle to get the Blushhh Music name out, traveling to as many as a dozen cities in a month to sit down for TV appearances and perform in radio-showcases. “We’re getting opportunities because the timing is right for a girl group,” says Knowles. “Some of these radio shows, it’s all men and they need girls.”

In September, the trio and Knowles started filming a reality show with Bunim/Murray, the production company behind The Real World, Project Runway and Keeping Up with the Kardashians.

Through it all, the specter of Destiny’s Child hangs over the women, as both an inspiring force and a virtually impossible standard of perfection. “You know that saying ‘What would Jesus do?’ We get ‘What would Destiny’s Child do?’” says Sunni. “He does use it as a motivator.”