Parrot MKi9200 & amped rear speaker issues

[Rfmacaskill]

I installed a parrot BT handsfree kit MKi9200 last year. The BT system works really well but I never bothered playing any MP3 music till now. All MP3 music only comes from the door tweeters.

I believe it's because the main door & rear speaker is amped. It's the original Concert audio tap deck head that's in the car.

Any suggestions re where I can purchase the appropriate wiring loom / box of tricks to make the system work properly?

 

[Rfmacaskill]

Sorry, just realised this is the wrong forum...have reposted correctly

 

[aragorn]

the front door speakers are all connected to the headunit. The tweeters and midbass are simply in parallel.

The rear speakers are driven by a small amplifier in the rear.