Re-reading, I see I was a little too brief.
You would need a USB/Serial adapter such as mikroe483
connected to Serial1, Serial2, Serial3 to be able to have 4 total USB ports.
None provide USB host capability, need a USB Host shield or equivalent for that
to be able to control a USB hub as far as I know.
I don't know if code exists to control the hub either, might be breaking new ground there.