add_to_entourage_but_not_court_effect

add_to_entourage_but_not_court_effect = {
	#If the character is a pool character
	$NEW_COURT_OWNER$ = {
		if = {
			limit = {
				exists = capital_province
				$CHAR_TO_ADD$ = { is_pool_character = yes }
			}
			current_travel_plan ?= { add_companion = $CHAR_TO_ADD$ }
			$CHAR_TO_ADD$ = {
				hidden_effect = { move_to_pool_at = $NEW_COURT_OWNER$.capital_province }
			}
		}
		#If the character is NOT a pool character
		else = {
			if = {
				limit = { $CHAR_TO_ADD$ = { NOT = { exists = current_travel_plan } } }
				current_travel_plan ?= { add_companion = $CHAR_TO_ADD$ }
			}
		}
	}
}

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