This sounds like a collaborative inbox.
Such an inbox is basically a Google Group, with some special attributes. It can be used to delegate tasks to group members, amongst other things. And it allows group members to send messages on behalf of the group, using the group's email address as the
To create a collaborative inbox, first create a group from your Google Apps control panel (http://www.google.com/a/example.com). On the group members screen, click Add all users in this domain:
Then go to http://groups.google.com, find the group settings, and set it up as a collaborative inbox:
Messages sent on behalf of the group must be sent from the Google Groups web UI, where you can choose a