How can I keep Windows 7 from making bluetooth headset the default sound device when it is plugged in?

I have a client with a windows 7 (64 bit) machine with speakers and a bluetooth dongle/headset. The speakers need to be the default sound device and it is set as such.  

The headset will be used by a patient for music/video.  The speakers are used for inter-office communication via a fancy third party software package with multiple chimes and bells to alert the practioner of needs elsewhere in the office.  This software cannot be configured to go anywhere.  It uses the default sound device.

My bluetooth adapter is a Zoom USB Bluetooth Model 4314 and the headset is a Go groove Air Band.

The dongle/headset pair and work fine.  Windows media player is configured to use the bluetooth device/speakers.

The problem is that as soon as the headset is turned on, Windows 7 changes the default sound device to the bluetooth device/speakers.
Note that when the headset is turned off, the default device reverst back to the speakers.

I have REPEATEDLY configured the normal speakers to be the default device, but the bluetooth consistently becomes the default device when the headset is turned on.

Having the office staff change the default every time they turn on the headset is NOT an option.