Practiced Cohort( Heroes of Battle, p. 99)
Your cohort works well as part of your team.
Leadership (PH) , CHA 15,
Your cohort gained from the Leadership feat gains any teamwork benefit (see Teamwork Benefits, page 115) for which you qualify, even if he or she doesn't meet the team member prerequisite for the benefit. In addition, your cohort doesn't count against the normal limit of eight members on a team, and his or her presence on the team doesn't affect any other character's ability to qualify for the teamwork benefit.
If you do not have this feat, every member of a team must meet the team member prerequisite in order for anyone on the team to enjoy the teamwork benefit. Also, the maximum number of members in a team is eight.