design pattern needed (for C#)

[C# Programming]

I'm lookin for a design-pattern that match what I need: I have class A which should hold a collection of class B or its inehrited classes. class B should be able to run functions and access properties on A and A should be able to run functions and access properties on B.

I've been suggested to pass reference of As properties to B opon construction, but I'm lookin for the design-pattern...

anyone know of any design-pattern similar to this?
Thanks alot http://www.barakasoft.com/script/Forums/Images/smiley_smile.gif

NaNg.