Joda,
What you are looking for does not exist in any AVR I am aware of, among the unsupported features are independtly controlled volume for each pair of speakers.
- Also, many multi-zone AVRs do not support digital inputs to some or all of the "extra" zones and four zones is a very high number in the AVR business.
You would be better served looking into
Sonos, or another similar distributed audio system instead to do what you describe.
Cheers,
XEagleDriver