I've no problem on sending messages! I send at most seven contemporary asynchronous messages (one process for each message to device)to seven different devices (it work very well). The problem is on discovering! When I scan for bluetooth devices where there are more than one hundred mobile devices You may even need to wait more than 5 minutes before the end!
I'd like to stop the discovering function for example after the first 20 devices founded and then start with message sending.