Karma Beacon (Fallout Supplement)
From D&D Wiki
Your morality shines twice as bright.
Prerequisite: Charisma 14, An Allegiance
Benefit: When dealing with someone with the same allegiance as you, you gain a +4 to Charisma-based skill checks instead of +2.
Normal: Person gains +2 to Charisma-based skill checks when dealing with someone with the same allegiance.