'X Factor' Recap: Simon Cowell Lets 'Adorable' Couple Into His Final Four

Judges round out the final 16 on Thursday night's episode, bringing the Four-Chair Challenge to an end.

Simon Cowell solidified his final four picks in the Groups category on Thursday's episode of "The X Factor," rounding out the competition's 16 finalists and bringing the Four-Chair Challenge round to a close.

Making the grade in the category are Michigan-based sister act Roxxy Montana, cutesy duo Alex & Sierra, and two groups put together by the judges, Sweet Suspense and Restless Road.

Cowell seemed most impressed with Roxxy Montana, a trio of sisters from Wayne, Michigan, whose parents are both preachers. "Here's what's exciting about you three: For whatever reason you haven't quite worked out who you want to be, what you should be doing. And let me tell you — we could make you incredible," he told them after they sang Michael Jackson's "Man in the Mirror." "I have a feeling about you three. Because you have the talent, you really, really do."

Roxxy Montana nudged aside Forever In Your Mind, a male threesome who made it through their round — with hesitations by Kelly Rowland, Paulina Rubio and Demi Lovato — after singing the Jonas Brothers' "Lovebug."

Alex & Sierra are a duo who could barely keep their paws off each other long enough to get through a song together. While singing a slowed down version of the "Grease" hit "You're the One That I Want" Alex leaned over and pecked Sierra, and while waiting for the judges to weigh in, Sierra started biting Alex's shoulder.

The judges found this endearing. "I genuinely adore you two," Rowland told them. Lovato had the nerve to question what would happen to their career if or when they were to break up, while Cowell dismissed the mere notion of them parting ways. "These two I can't ever see splitting up," he said. "People are going to fall in love with you." The duo's inclusion knocked out Girls United, a pop trio who were the first group let through to Cowell's final four.

Sweet Suspense, a trio of girls ages 14 to 17, was put together from contestants who tried out as solo artists. Their version of Beyoncé's "Wishing on a Star" impressed the judges, and Rubio said they looked like "superstars" on stage. Cowell let them through, praising their chemistry, talent and ambition, and they knocked out the party rock duo Wild Thingz, who crashed the stage the night before with a manic act that found them running around the stage like middle schoolers hopped up on Red Bulls. Wild Thingz, you will truly be missed.

Restless Road earned a standing ovation with their version of Keith Urban's "Somebody Like You," and the "country man band" — made up of three singers who auditioned as solo artists — gave Lovato "chills all over my body." Cowell, smitten with his own work in putting the three males together, said he was really impressed with the group, which he was able to make just as much a compliment of himself as the singers.

Glamour, made up of three best friends from Atlanta, were briefly in the final four but were cut over the course of the evening. And the groups Yellow House Canyon and Good News were cut before having a chance to have a seat in those all-important chairs (which, for the groups, were actually couches, but the Four-Couch Challenge just sounds weird).

Now that the 16 finalists are set, viewers have to wait nearly three weeks to see them perform, due to Fox's obligations with the Major League Baseball playoffs. The "X Factor's" live shows are set to begin Oct. 29.