I - Rules
(see JITD, p. 23)
Sweep attacks affect all enemy figures within melee range of the attacker. The Sweep ability deals its full damage to each figure affected by it. If a Sweep attack is dodged by more than one figure, only one re-roll may be made (the first dodging player to the attacking player's left decides which dice, if any, are to be re-rolled).
II - References
Heroes with the Sweep ability: Eliam (3 fatigue for 1 melee attack).
Feats granting the Sweep ability: Sweeping Blow (1 melee attack only).