Many departments would like to have a departmental email address or calendar which allows access to a specified group of people. While there is no Andrew account type which allows group access, there is an alternate methods to allow group access to email and calendar.
To request a Shared Mailbox/Calendar for a group, visit MyExchange Tools.
To use the Shared Mailbox/Calendar once it's created, follow the appropriate steps in the Shared/Mailbox Calendar document.
Google Apps @ CMU
See the Google documentation on sharing your calendar.