The 6500 can only via connected via ethernet. The radio has a RJ-45 connector on the rear for a wired ethernet connection. I have no idea if it would be possible to use some sort of external ethernet to bluetooth adapter.
As far as I can tell there is no Bluetooth capability built into the Flex 6500. If the unit has an imbedded windows 10 operating system, which I think it does, it is possible that a Bluetooth dongle might work on the usb port assuming the drivers are present.