Creating common controllers

[eluser]patilshailesh[/eluser]
Dear
thanks for your reply. Very much near to what i am trying to acheive.
My goal is to have common controller.

My folder structure will be:
Project
MainCI
application
controllers
user.php
models
userm.php

App1
application
controllers
user.php
models
userm.php

App2
application
controllers
user.php
models
userm.php

I want App1 user controller should be inherited from MainCI user controller.
Functionality will be almost same. In case i need more, i can add in App1 or App2 controller function.
Is it possible? how it can be done?