Social web site in 3 level

I wonder if it is possible to have a front office managed as a CMS. I wish to make a3-level site:
- 1st level: it is the visible part of the public site and contains the information of the association. it will be a dynamic part with updated information regularly.
- 2nd level: it concerns three group members. Each group is run autonomously. in each group, the members exchanged email, publish articles and send files. they have the opportunity to chat.
- 3rd level: It covers the general administration of the site. The administrator can interacton all levels. Publish articles at one and act on the contents of level 2.
What modules can I use for this project?
in addition we need a suitable design.

Hello, No body have an idea? Please give me help

Short answer - yes Dolphin will do this.

slightly longer answer...

you will need to spend time on this, how much depends on how much site content you will have...

Use the following

Page Access Control - built in mod on latest D versions that allows you to set viewing and access permissions over pages, top menu link etc..

Deanos Enhanced Block Visibility - allows you to add specific group viewing rights to individual page blocks.

The rest is setup in members permissions. 

Can all be done though, just will take time to set up.