My Paparazzi version is v5.3_devel
you don't need to use XBee API mode for multiple aircrafts, you just can't send messages to only one specific aircraft.
So it should work fine with your setup (transparent/same PAN/each has unique ID).
Btw, you don't need to change the baudrate (that is only the baudrate of the uart interface to the XBee, doesn't change the over-the-air baudrate).
This sounds like a bug, what paparazzi version are you using?
I'm sure we can sort this out.
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