USB-Serial Arduino to 3D printer board communication

I'm using a few different 3D printer boards which accept communication very similarly to Arduinos (i.e. internal usb-serial FTDI chips). I would really like to use an Arduino to send serial commands to these boards. However, I don't necessarily have RX-TX pins accessible on the 3D printer boards, just USB.

Can you think of an effective way to do this? I was thinking of connecting the RX-TX pins on the Arduino to an external FTDI converter and then using a male-to-male USB cable to connect to the 3D printer board (see attached diagram). I simply don't know whether this can work with the Arduino as host.

Thanks for the input!

Isosceles:
I'm using a few different 3D printer boards which accept communication very similarly to Arduinos (i.e. internal usb-serial FTDI chips). I would really like to use an Arduino to send serial commands to these boards. However, I don't necessarily have RX-TX pins accessible on the 3D printer boards, just USB.

Can you think of an effective way to do this? I was thinking of connecting the RX-TX pins on the Arduino to an external FTDI converter and then using a male-to-male USB cable to connect to the 3D printer board (see attached diagram). I simply don't know whether this can work with the Arduino as host.

The FTDI board will only talk to a USB Host, not another USB Device. You will have to connect RX, TX, and Ground to the 3D Printer Control Board in place of the built-in USB-to-TTLSerial chip.

Darn. Thanks for shooting this one down before I wasted too much time!

You could try a "USB Host Shield". I don't know if they support USB hubs so you may only be able to use it to talk to one client.