You can specify the USB device to export by USB id in the form of <vendorid>:<prodid>.
Notice that an instance of usbredirect can only be used to export a single USB device and it will close once the other side closes the connection. If you want to export multiple devices you can start multiple instances listening on different TCP ports.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.