Hello.
I will explain how the Group Skills work and used for.

Group Skills are a great way to improve your power in Naruto Online.
You can get the points by completing Group Convoys, Plundering and Group Donations.
Each Group Skills boost a certain stat:
Life Gains: It will improve your team's health.
Attack Gains: It will improve your team's normal/taijutsu attack.
Ninjutsu Gains: It will improve your team's abilities/ninjutsu skills.
Defense Gains: It will boost your team's defense which will reduce the normal attacks from your enemies.
Resistance Gains: It will improve your defense against enemies' attributed skills/abilities.
Taijutsu Shield Pen.: It will help *e the defense of the enemy when attacking with normal/taijutsu attacks.
Ninjutsu *ion: It will *e/ignore the resistance of the enemy when using abilities that cause ninjutsu.
Damage Reduction: Self explanatory. It will reduce the damage done by oneself.
Life Recovery: Each round, you will recover the amount of HP. Depending the level of the group skill.