I worked on my bluetooth tracking app a little more last night adding the capability to receive device updates from other BlueTrackers. I did this by adding xPL so that the app will generate xPL messages when it detects a phone or when that phone times out. Other BlueTrackers on the network, which may not be close enough to the phone to detect it, receive those xPL messages and can then update its list of present phones. My HA software can now key off phone detected messages from all BlueTrackers to establish that a phone is home. When a phone leaves the house, eventually all BlueTrackers will issue timed out messages, but only one BlueTracker will serve as a master - and only messages from that BlueTracker will be used to determine if a phone is no longer home. The app has been running on two machines overnight and is pretty much done.