A character fighting in close combat can always choose to allocate their attacks against enemy models in back-to-back contact [sic?], unlike ordinary troopers who may only do so if their opponents have different Weapon Skills and Strengths. A character's attacks can be divided up as the player wishes, as long as they makes it clear before rolling to hit.
If a player chooses to allocate attacks in this way the character can only inflict casualties on the models in base-to-base contact with him. It can be imagined that the character is deliberately looking to cut down those before him instead of rampaging
Diagram: Allocating Attacks. A Chaplain character stands in base-to-base contact with two enemy models simultaneously - an Ork character and an Ork warrior. Caption: "The Chaplain is fighting both an enemy character and an ordinary warrior, and so can allocate all of their attacks against the warrior, or all of their attacks against the opposing character, or divide them between their two opponents as they wish."