In attempting to solve this issue, I believe I have successfully extended the official Android Bluetooth Chat example to work with a server connecting to multiple clients.
I've uploaded my modifications to github here:
One device acts as the server by selecting "Menu>Make discoverable". Each client then connects by selecting "Menu>Connect a device". I was successfully able to connect my Motorola Droid and HTC Eris as clients to my Samsung Galaxy Tab 10.1". Each message sent from a client displays only on the server. A message sent from the server displays on all clients.
This was a tedious process getting it to work at all. Connectivity with the HTC devices is sporadic, though. I've read elsewhere that bluetooth on HTC is buggy, so I'm chalking it up to that.
Hopefully someone else will find this example useful. If you have any questions, suggestions, or other feedback, please let me know.