So I have a 9th level party, with 7 players. A fighter/barb, a wizard, a spirit shaman, a ranger, a monk, a rogue, and one bard.
The bard's fighting song, with feats from Eberron, gives the party +3 attack/+3 damage. So assuming all hits:
Fighter/Barb: 3 attacks +9 damage
Ranger: 4 attacks...