Group Tactics (3.5e Feat)
From D&D Wiki
Group Tactics [General]
You have trained in group tactics; you have learned to coordinate your attacks and create openings and opportunities when ganging up against a single target.
Prerequisite: BAB +1
Benefit: You gain a +1 to your melee attack roll when you and one or more allies team up to fight the same opponent. If any of your allies also possess the Group Tactics feat, the bonus is increased to the number of attackers who possess the feat (with a maximum bonus of +3).
Special: A fighter may take Group Tactics as a bonus feat.