add_clan_unity_interaction_effect

add_clan_unity_interaction_effect = {
	if = {
		limit = { # Check if unity is relevant
			$CHARACTER$ = { government_has_flag = government_is_clan }
			$TARGET$ = { government_has_flag = government_is_clan }
			exists = $CHARACTER$.house
			exists = $TARGET$.house
			$CHARACTER$.house = $TARGET$.house
			trigger_if = {
				limit = {
					exists = scope:actor
					exists = scope:recipient
					scope:actor != scope:recipient
				}
				NOT = { $CHARACTER$ = $TARGET$ } # As a safety, let's make sure that we are not interacting with ourselves
			}
		}

		apply_clan_unity_interaction_effect = {
			CHARACTER = $CHARACTER$
			TARGET = $TARGET$
			DESC = $DESC$
			VALUE = $VALUE$
			VALUE_REVERSED = no
		}
	}
	else_if = {
		limit = { # Only apply reversed effect for the house head to keep the gauge in check
			$REVERSE_NON_HOUSE_TARGET$ = yes

			$CHARACTER$ = { government_has_flag = government_is_clan }
			$CHARACTER$.house ?= {
				house_head = $CHARACTER$
			}
			OR = {
				AND = {
					exists = $TARGET$.house
					NOT = { $CHARACTER$.house = $TARGET$.house }
				}
				$TARGET$ = { is_lowborn = yes }
			}
		}
		apply_clan_unity_interaction_effect = {
			CHARACTER = $CHARACTER$
			TARGET = $TARGET$
			DESC = $DESC$
			VALUE = $VALUE$
			VALUE_REVERSED = yes
		}
	}
}

As written in game/common/scripted_effects/00_interaction_effects.txt.