As DragonChild suggests, you ought to take a more component oriented
approach, assembling the final product from base components.
I would probably have something along the lines of the following
classes: CDPlayerInterface, RadioInterface, AudioDeviceInterface,
CDPlayer, Radio, and RadioCDCombo. The Radio class would be a
marriage of the RadioInterface and AudioDeviceInterface, the CDPlayer
class would be a marriage of the CDPlayerInterface and the
AudioDeviceInterface, and the RadioCDCombo class would be a marriage
of CDPlayerInterface and RadioInterface and AudioDeviceInterface.
Or something like that... I'm not sure I like the specifics of
my solution, but I think the general paradigm is better.