So tell me what I need to get here:

I have a Harmon Kardon 235 RX with preamp outs.
2 speakers front porch (zone 1)
2 Speakers back porch (zone 2)
2 speakers Garage (zone 3)

I want to drive these from my HK 235 and I want to be able to have at least the front and back zones turned on at the same time or individually. This amp also drives a 5.1 in the living room which will be carrying the same source (ie. Foot ball game party, and have people out back or outfront who can hear it)

Outdoor speakers are Klipsch Reference with 5-6" woofers

The Garage can wait for another day...

So I was looking at the Audio Source 50 watt per channel a/b amp.
so I guess what I need to do is go from the preamp outs to the Audio source, and then that goes to the speakers.

But what is the best amp I can use with indipendent or combined zones for at least two zones in the sub $300 range?

That being asked: could I take another reciever with dual zones and preamp out to one of its inputs, and use the zones from it?

Thanks
kirby