How To Sub Class An Existing Controller

[eluser]Unknown[/eluser]
I have found lots of information on this for extending the base controller but not for extending other controllers. I already have a MY_Controller which is working great for what I need to do. My application is made up of different portals. One of the things that 2 of the portals manage are properties. The code between the 2 portals is 99% the same. I am wanting to create 2 different controllers but have the inheritance look like this

MY_Controller --> PropertyBase --> PropertyContractor

MY_Controller --> PropertyBase --> PropertyManager

Is it possible to do this?

Thanks

Paul