The Bluetooth on the TXNR636 is input-only (eg to connect your phone and play music from the phone thru the receiver).
From what I read, LS3100 is blue-tooth enabled audio receiver. So, you have two input devices...
The only way (and I don't know how well it will work) is to get Blue-tooth audio transmitter, connect it to 636 output, and pair it with LS3100.