Announcing: Connected Groups Add-on
Creates shared groups between different Gmail accounts.
Connected Groups add-on uses a spreadsheet as a master list to create shared contact groups. Each person who is shared is called a Manager, each manager can add or delete names from the list, as well as invite other users to become managers and use the shared contact list. Any changes to the lists get updated to all the managers over the course of an hour. Managers can choose to sync or not sync. One possible scenario is a secretary needs to manage a contact group for a school principal. The secretary is in charge of keeping the contact list up-to-date. They can install Connected Groups and updating the list will be as easy as adding a name to a spreadsheet.
To see more of my scripts check out: https://sites.google.com/site/edlistenscripts