[dba-VB] C# protected

I am trying to create a method of a ClassA which can be seen from the object ClassB that 
instantiates ClassA but not by objectClassC which instantiates ClassB.

IOW ClassA "belongs to" ClassB so specific methods / properties of ClassB should be manipulateable 
by ClassB.  However those properties / methods should not be visible to anything outside of ClassA 
and ClassB.

Possible?

Oh, and BTW I want ClassA to be out in a class library, external to the project using it.
-- 
John W. Colby
www.ColbyConsulting.com