R820 Internal USB - Expandable ?

I currently use the internal port to connect  a USB security key (Sentinel). It turns out I need to add a second dongle.

Before I go out and buy a cable splitter to try, I would like to know whether connecting two usb sticks via a splitter cable would be supported by the MB. I would think the power draw would be minimal, and speed is not a concern at all. These are accessed by the program when it starts up, and then a once every few hours.

I can put the dongles on the external ports obviously, but prefer internal for physical security. Thanks for your thoughts.