In Chapter 10, one way in which Ralph, Piggy, and the twins Sam and Eric, often called Samneric, distance themselves from Simon's killers is by banding together. In Chapter 10, first Piggy finds Ralph as he emerges from the woods, then Sam and Eric emerge from the woods to join them after collecting wood, which is there means of grouping together. Not one of the boys wants to join with Jack and the others. As Roger phrases it when he comes to join the boys from Jack's group, "[Roger] had reckoned, during the terrible night, on finding at least some of the tribe holding out against the horrors of the island in the safest place." They continue to separate themselves from Jack and the rest by making their own fire and lying down in their own shelter. Remaining physically separated from Jack and the others is one of their ways of separating themselves from the murder.
A second way in which they separate themselves from Jack and the others who instigated Simon's murder is by denying that they had actually participated in the dance. Both Ralph and Piggy claim that they had remained outside of the dancing circle, while Sam and Eric even claim that they left early after the feast and got lost in the woods before the dance started. They even try to deny that the murder took place, which is another way of trying to separate themselves from both the event and the murderers. Only Ralph acknowledges the horrible crime for what it was; Piggy insists on calling it an accident.
Finally, they distance themselves from Jack and the others by thinking differently from the others. Specifically, they acknowledge that if they remain on the island, they'll go out of their minds like Simon's killers. Their ability to judge Simon's killers as insane proves that they think of themselves as different from the others, which is another psychological means of distancing themselves from Simon's killers.
Ralph, Piggy, and Samneric attempt to distance themselves from Simon's killers by thinking differently from them. Both sides had different opinions and different plans. Not only did they mentally separate from them, but also, obviously, physically got separated. All four of them grouped together and moved away from Simon's group, when Simon's group did dances, attacked them, etc.