Connecting speakers to two separate integrated amp

This is my first post on A-gon ... looking forward to getting everyone's input :)

Here's my situation. I have a pair of Proac Response 2s that are currently part of my 2-channel audio system (connected to a Peachtree Nova). In the same room I also have my 5.1 home theater system. My left and right speakers for home theater are currently B&W CCM-80 in-ceiling speakers (connected to a Denon A/V Receiver). I want to use the ProAcs for both the 2-Channel system and the 5.1 home theater set up. My center channel is a B&W HTM2.

Is it ok to connect both integrated amps to a single pair of speakers? I don't plan on having both systems on at the same time, but if somehow both systems were "on" and sending signals to the speakers could I potentially damage the speakers, the Peachtree, or the Denon? Even if only one of the systems is "live", could I damage the other system?

Thanks in advance
Connecting speakers to two different amps will eventually lead to disaster, at least it would for me. I have the same 2-channel and 5.1 set-up that you are after and use an integrated amp with a home theater pass-through. This in effect, allows your denon receiver to act as the pre/pro and the integrated amp as amplifier while you are in "pass-through" mode. Simply leave the receiver off for 2 channel listening. Otherwise, I would look for a high quality speaker switch.
Get yourself a Niles SPK-3 switch box. It will allow you to connect two amplifiers to one set of speakers safely.
How does your peachtree sound on the proacs?

If the peachtree doesn't have a ht passthrough, just choose a volume level you will always set it on for ht (eg 12:00) and run the lr front out into an analog in on your peachtree.
The Peachtree pairs very nice with the ProAcs. I've also run the Peachtree with some Paradigm Studio Reference 20s and Spendor SP2s and they also pair well. The Peachtree system preserves the audio engineers' intended sound for each of the speakers ... classic British and Canadian sound.

As for my question let me clarify what I'm trying to do and how things are set up.

In front of room the Peachtree Nova is connected to an iMac (via USB) and a Marantz CD Player (via analog and optical). The Peachtree is connected to the ProAcs and is solely for 2-channel audio.

In the back of the room I have the HT rack (Denon A/V receiver connected to multiple sources outputting to a projector) Inside the rack I've got a bunch of speaker connect options to the front of the room. Three to in-ceiling (L/C/R) speakers (L/R currently in use) and three that terminate under the screen (L/C/R) (only C is use).

I'd like to use the L/R in-ceiling as L/R height speakers. The C that terminates under the screen is currently connected to the HTM2. Can I connect the L/R that terminates under the screen to the ProAcs while the ProAcs are also part of the Peachtree system?

Also a couple of member suggested using a speaker switch. Are speaker switches for single amplifier/multiple speakers configurations or are there ones for multiple amplifier/single speaker configs? Also trying to keep the system as simple possible for high WAF.