I don't think you are going to be able to do what you want with the bluetooth implementation on the PE - I'm ready to stand corrected if someone has done it
By far the better way would be to have an FTP Server on each device and use it and es-file explorer to transfer files via a WiFi link.
The WiFi router should give each device an IP address and with the FTP Server running, ES File Explorer FTP tab should allow you to log on to each unit. You can also use FileZilla on your PC to download from the edges.
I use SwiFTP on my EE to allow me to download from it to clients machines and ES File Explorer to connect to my two company and home FTP servers. I have been using this setup from day two of owning my EE and have not found any problems and yes we do have login security enabled on all servers.
If you need details of how to set this up just ask and I'll look up my notes. As an aside you don't need root privileges to set up FTP.