USB Host to USB device

Interesting yet strange question. I would like to connect the USB end of a USB to Serial adapter to "X" device. This "X" device would act as a USB host and convert the incoming data back to serial. From here, I can add a bluetooth Serial link, wifi, Ethernet ect, and on the other end convert it back from Serial to USB.

I know the first question will be "Can you just bypass the initial USB to serial adapter?"
-No I cannot. The product I am trying to retrofit is an enclosed system.

Thanks!!!

It is unclear what you want to do, but programming a USB host interface is daunting. You can get a Host shield or I believe the Due can act as a host.

I want to intercept the RX/TX data coming through and inject special code. Making it either a wireless device or dual connections.