If you're part of an enterprise association that allows for memberships to be registered (such as national memberships) and shared to another organisation you want to know when a new member has joined you or renewed - just like you do with 'local' memberships.
To setup this feature head to Organisation Settings > Association Settings > Notifications
You will need to ensure that you have some Roles so you can send notifications to a Role which in turn bounces the notification email to whoever is in that Role for the organisation.
For example if you want the Secretary to be notified of anyone that joins that organisation, then head to Roles and establish the Secretary Role and assign the Role to a person.
This works for New Members and Renewing Members who register.