Originally Posted by TNA 'The very best'
I see it a bit differently for that to happen. Cena can see that Barrett has treated his team very poorly (which you saw when Cena disliked how Otunga simply dropped the title). In the comming weeks, we see similar treatment with the others as Cena continues to complain about it. Behind the scene (and off camera), the group outside MM, HH and Barrett go to Cena and wish for him to become the leader of Nexus. Cena, seeing the power Nexus has, decides controlling them would actually be good for his career and take them over behind Barrett's back.
Then after Survivor Series when(if really) that happens, MM and HH become confuse as to what they want to do. They want to join Nexus, but it is Cena who is in charge. Wade tries to convince them to join him since Nexus is nothing without him and after a few weeks they decide to stay with CeNexus by giving Barrett the treatment they usually do. This will eventually lead Cena to win the title from Orton and use his new powers to keep the title, until he loses it thanks to the Undertaker.
Without knowing, by becomming the leader of Nexus, he also inherits the troubles of Nexus, which was them burying him when Kane gave Barrett an offer he couldn't refuse. This leads to a Taker/Cena match at Wrestlemania in which Taker takes out each member of Nexus one by one until there is only Cena left so it'll be a clean one on one fight between face Undertaker and heel John Cena.