L.A. Reid throws a tantrum on 'X Factor' By Katy Kroll, Rolling Stone Nino Munoz / Fox The boot-camp bloodbath spilled over into this week's "X Factor," as the top 24 acts were revealed and quickly divided into four categories: Teens, Young Adults, Groups and - hold onto your prunes and walkers everybody - Over 25s. While the Groups category is a holdover from last season, all the others are new - replacing Boys, Girls and the walking dead known as the Over 40s. This time, the "old-timers" tap out at exactly 40 with Vino Alan. More from RollingStone.com: Video flashback: Elton John and Eminem unite Apparently even that is too old for L.A. Reid. Because when it came time to divvy up the categories amongst the judges, he had a mini-meltdown when the producers called to say he'd be mentoring the "Overs." After slamming down the phone, he stormed off in a huff. Way to have confidence in your team, L.A. Then, when his geriatric protégés showed up on his million-dollar doorstep looking for the guidance they were promised in the lazily-named Judges' Homes round, he gave the worst pep talk ever. "I can't really say that there's anybody that stands out in this category," he griped. I'm not happy, but I still plan on winning. Yeah, that really makes us want to vote for your team. Hoping to breathe some life into the seemingly hopeless situation, Reid will be relying on guest mentor Justin Bieber to offer the kind of sage wisdom that comes with turning 18 and lasting three whole years in the music industry. Also mentoring are will.i.am alongside Britney Spears and the Teens; Nick Jonas with Demi Lovato and the Young Adults; and Marc Anthony and Simon Cowell for the Groups. Speaking of groups, there were only three that made it through boot camp. Then, three more were manufactured by the judges using singers who didn't quite cut it as solo artists. While this maneuver could have backfired, they each came together nicely once they arrived at Simon's home to audition yet again. Yes, there's more paring to be done, as the six acts in each category will be cut to four before the live shows begin. The clear standout on Simon's team was hip-hop trio Lyric 145, comprising badass one-eyed rapper Lyric Da Queen and male duo One4Five. Their version of Miley Cyrus' "Party in the U.S.A." was killer, and the look on Simon's face when they finished said it all: We have a winner! More from RollingStone.com: Premiere of Paul McCartney's live 'Letter' Meanwhile, over at Demi's house, she and the baby Jonas brother sifted through the Young Adults talent, which unfortunately included Paige Thomas and Willie Jones. Seriously, time to dump them, guys. And while CeCe Frey was told she isn't very "likable," she definitely has the vocal chops and stage presence to stick around. Her jazzy rendition of the most overdone song of the season, LMFAO's "Sexy and I Know It," set her apart from the rest of the pack. Now, someone just needs to scrub those leopard spots off her face. But that'll have to wait till the next ep, where we'll see what the other categories have to offer and (hopefully) find out who makes the final cut. In the meantime, here's a quick rundown of who's in what group. Teens: Beatrice Miller, James Tanner, Carly Rose Sonenclar, Diamond White, Reed Deming, Arin Ray. Young Adults: CeCe Frey, Willie Jones, Jennel Garcia, Nick Youngerman, Paige Thomas, Jillian Jensen. Over 25s: Jason Brock, Daryl Black, David Correy, Tara Simon, Tate Stevens, Vino Alan. Groups: Sister C, Dope Crisis, Emblem3, Lyric 145, unnamed boy band, unnamed girl group. What did you think of L.A.'s reaction when he learned he was mentoring the "Overs"?