Stereo mute and radar detector/gps

[jwolk1]

I installed a Sony-Ericsson bluetooth hands-free kit with the HCE-16 advanced music mute harness - for anyone who has a bluetooth phone I highly recommend it - it will mute my stereo when a call comes in and unmute when the call is finished, allows for voice activated dialing, plays the audio through my car speakers, and allows me to have the phone in a briefcase in the hatch and still answer it. This got me thinking as to how I could accomplish the same thing with my Radar Detector and GPS (both of which give audible directions and have an "external speaker" type jack). In a utopic world this is what I would like to accomplish:

(1) Muting the car stereo when a radar detector or gps gives an audible instruction.
(2) Playing the audio through my car speakers.
(3) Have a switch that will allow me to decide whether the audio actually mutes the stereo (say for long trips I would want it on and short trips I would want it off)

I did some searching and have found that some people use a relay hooked up to the accessory wire to actually turn on and off the radio. I suppose a simple switch could be added to use or bypass the relay ultimately accomplishing #3. By the way I have a KLH series JVC Head Unit - it doesn't have a mute wire. Has anyone else rigged something up like this? I am open to any other suggestions or solutions for accomplishing the above - Thanks -

Jeremy

[CSU944]

I think it's all possible, but with a lot of wiring involved. What model head unit, GPS, and radar are you using?