Weird Setup - Will it Work?

I am helping a friend buy a new stereo, and she wants it to control speakers in two room (living room and kitchen). She also wants a tuner. I am steering her toward a Portal Panache amp, and originally thought she could use her old NAD receiver for the tuner. Now that I know she wants two sets of speakers, and that both speakers should be able to play the tuner and the CD player, I thought of this setup, but am wondering whether it would be potentially dangerous as it could set up a feedback loop between amplifiers. Here it is:

- Tape out from NAD receiver goes to Panache input #1
- CDP goes to Panache input #2
- Tape out from Panache goes to NAD input #1

When she wants to play the tuner, she simply switches her NAD to FM and her Panache to input #1. When she wants to play a CD she simply switches her Panache to input #2 and her NAD to input #1. The potential problem arises if she has the both the Panache and the NAD switched to input #1 at the same time. In this case, the Panache is "hearing" and outputting the NAD, and the NAD is "hearing" and outputtng the Panache. That makes a loop. Are preamplifiers any more immune to the potential feedback problem that could ensue?

The way around this would be to buy a CDP with two outputs, such as a Jolida. But I'm trying to save her money and get a less expensive CDP (e.g. Cambridge Audio 500SE, which I think is quite good sounding in its price range). So, I'd like to stick with the first approach. OR - any other ideas? If not, I'll be asking for recommended integrateds or receivers with two switchable speaker outputs!

Thanks.