The TX and RX LEDs are controlled by the USB to serial converter on the board, not the Arduino chip. Since the USB to serial converter is not involved in sending data from board to another via the RX and TX pins, there is no reason to expect the TX and RX lEDs to blink.
Correct me if I'm wrong, but what I am taking away from this is that I shouldn't even be trying to use the TX and RX pins as outlets for transferring data because its proper use is for applications involving an arduino board and a PC or USB.
So I believe now my question is, how the heck am I going to get this controller of mine to continuously feed data from three variables from one arduino UNO to another?