tgp_on_member_house_joined_shared_effect

tgp_on_member_house_joined_shared_effect = {
	save_scope_as = bloc
	scope:house ?= {
		save_scope_as = joiner
		set_variable = {
			name = recently_joined_bloc
			years = 5
		}
	}
	# MESSAGES
	every_player = {
		limit = {
			top_liege ?= scope:bloc.leading_house.house_head.top_liege
			tgp_uses_house_blocs_trigger = yes
		}
		if = {
			limit = {
				NOT = { house = house.house_confederation.leading_house } # avoid double message when creating
				scope:bloc = {
					any_confederation_member_house = { count = 2 }
				}
			}
			send_interface_message = {
				type = msg_house_bloc_created
				title = msg_house_bloc_created
				desc = msg_house_bloc_created_desc
				left_icon = scope:bloc.leading_house.house_head
				right_icon = scope:bloc.leading_house
				custom_description = {
					text = create_house_bloc_effect
					subject = scope:bloc.leading_house.house_head
				}
			}
		}
		else_if = {
			limit = { house.house_confederation ?= scope:bloc }
			send_interface_message = {
				type = msg_house_joined_house_bloc 
				title = msg_house_joined_bloc
				desc = msg_house_joined_bloc_desc
				left_icon = scope:joiner
				right_icon = scope:bloc.leading_house
				custom_description = {
					text = join_house_bloc_effect
					subject = scope:joiner.house_head
					object = scope:bloc.leading_house.house_head
				}
				# MEMBER LIST TOOLTIP
				#show_as_tooltip = {
				#	scope:bloc = {
				#		every_in_list = {
				#			variable = joining_house_members
				#			limit = { house = scope:joiner }
				#			custom = house_joined_bloc_member_custom
				#			custom_tooltip = house_bloc_member_tt
				#		}
				#	}
				#}
			}
		}
	}
	every_in_list = {
		variable = joining_house_members
		limit = { house = scope:joiner }
		save_temporary_scope_as = house_member_temp
		remove_character_flag = bloc_message_flag
		scope:bloc = {
			remove_list_variable = {
				name = joining_house_members
				target = scope:house_member_temp
			}
		}
		# Find Sub-Vassal houses of joining Vassal Houses
		if = {
			limit = { is_independent_ruler = no } # Kampaku is the only exception
			every_vassal_or_below = {
				limit = {
					is_house_head = yes
					any_held_title = { is_noble_family_title = yes }
					is_independent_ruler = no
					house = {
						NOR = {
							this = scope:house
							house_confederation ?= scope:bloc
							is_in_list = joining_vassal_houses
						}
					}
				}
				house = { add_to_list = joining_vassal_houses }
			}
		}
	}
	every_in_list = {
		list = joining_vassal_houses
		save_temporary_scope_as = vassal_house_temp
		if = {
			limit = { exists = house_confederation }
			set_variable = {
				name = bloc_leaving_reason
				value = flag:reason_followed_liege
				days = 4
			}
			tgp_leave_house_bloc_effect = {
				OPINION = flag:no
				TRUCE = flag:yes
			}
		}
		tgp_join_house_bloc_effect = {
			INVITER = scope:joiner
			OPINION = flag:no
		}
	}
	if = {
		limit = { debug_only = yes }
		debug_log = "house joined bloc"
		debug_log_scopes = yes
	}
}

As written in game/common/scripted_effects/10_dlc_tgp_house_bloc_scripted_effects.txt.