Android Question Can you have different BT-profiles active between two devices at the same time?

From this thread Erel said:

Erel said:

You cannot emulate a headset with an Android device. The only Bluetooth profile accessible for developers is the SPP profile (serial port profile).
You can create an app that is installed on both devices and then communicates between them. It is pretty simple.

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OK, I have understood that part. I have tried the demo-app (chat app) posted by Erel in this thread and it works fine between two android phones.

Now, I have this android head-unit in my car running ICS 4.03 and there is already an existing and working bluetooth connection between my phone and the head-unit. The BT for this connection is "Call audio", "Media Audio" and "Contact access".

I now installed the BT sample app on the Head Unit and tried to get the chat app working so I could chat with the chat-app on my phone but it did not work out well. The devices are discovered but cannot connect. Is this because there is already an existing connection (pairing) between them and/or different BT-profiles cannot be used at the same (with chat-app = SPP profile)? Perhaps, I can simply check if they are connected and then use the chat-code? I have not yet tried this and I thought I would ask before if this is even possible for obvious reasons.

Thanks.