Hello, my friends and I like to bike on trails often and like to listen to music, but using a Bluetooth speaker is loud and annoying to other bikers. I was thinking it would be cool if you could build a Bluetooth transmitter capable of transmitting to about 4 Bluetooth devices at one time with a Aux in port so we could plug it into one Media Player. So we all could be wearing our own Bluetooth headphones linked to this transmitter device listening to the same song at the same time. Volume may be a problem because some Bluetooth headphones seem louder than others. But generally we could all listen to music and only have to have one person carry the iPod.