Girls Amelia Lily, Misha Bryan, last group Little Mix and sole boy Marcus Collins will no longer spend time together off set, according to Metro.
It was also claimed that Misha B locked herself into a Green Room during a warm-up for last weekend's show.
"The claws are out," a supposed source told the newspaper. "The guys can taste the final and they've stopped talking to each other.
"They all used to pop into each other's rehearsal studios to see what everyone was doing and what each had lined up but those days are definitely over.
"No-one is willing to even talk about what they have planned, so much so they've all been locking doors just in case another act tries to walk in."
They added: "Misha was warming up for Guilty Pleasures week and barricaded herself inside and was making sure no-one could see what she was doing.
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"A runner was literally banging on the door for her to come out and kicking it because they needed to come in but Misha refused to open the door."
The alleged insider said of Misha B: "She was once the favourite but has been shell-shocked by the rise in Little Mix's popularity.
"Misha went back to her diva ways this week because she was convinced she was back in the game after escaping a sing-off the week before. There is so much tension now between them all - friendship has taken a back seat."
Irish 17-year-old Janet Devlin was voted off the competition last night, with the judges opting to save Misha B after the sing-off.
Misha B has reportedly claimed that judge Tulisa Contostavlos damaged her chances of winning the show when she accused her of being "mean" to other contestants.
Following her own exit from the contest, Kitty Brucknell said that another singer had called her a "joke act" who could be ignored as competition.
Lily last week replaced Misha B as the star of the Marks & Spencer Christmas advert featuring contestants from this year's show.
Of claims that the change reflected a new tip for the winner, Marks & Spencer spokesperson said: "That is absolutely not the case. We have said right from the start that we would edit and change the ad."