We need a service something like campfire. It needs to run an instant messaging service in the background.
Let us know with which instant messaging service you have experience in the past and how many concurrent users it can handle. We prefer ejabberd or openfire.
The users registers and get an admin account. The client gets portal which looks a microblogging platform. The admin account is able to add users from its organization and they can chat. By deafult everyone is in the same roster but the admin can also create groups and assign users to it. He can also choose subgroup admins also.
The users can login and post to the portal or can chat within their groups or one on one with other people. All the chats are logged and displayed on the group page of the portal.
iOS, android and blackberry apps are also needed. Need to make sure our service is only accessible through our apps.
PM for further clarifications.