I'm working on a project in which I'd like to communicate between Processing using a serial port on a Mac and 2 different Arduino NG boards. I'd intended to serially chain the communication by connecting from my Mac to the first Arduino board via USB and then having the first Arduino board relay messages to the second Arduino board via a TX/RX pin connection. I'd hoped that when the first Arduino board resends a serial signal that it would be simultaneously broadcast across both the USB serial connection back to Processing and the TX/RX serial connection to the second board. As far as I can tell, though, the first board seems to not broadcast anything when the USB and TX/RX connections are both connected.
So, my basic questions are: (1) Am I right in concluding that this sort of multiple serial broadcast is not possible? (2) If it's not possible, can anyone recommend another means for sending the data from a computer to two different Arduino boards? I ultimately would like to just send a single byte across the network.
Thanks in advance! Casey