I don't think it can be done with the Cymatic. If you recall in HW's Audio Setup you pick the driver you want to use so the ASIO driver would only recognize 1 Cymantic at a time (the 2nd interface might appear as "ASIO-1").
Certain MOTU brand interfaces have an AVB port (Audio Visual Bridge) which is a relatively new IEEE protocol. Focusrite brand interfaces have adopted the Dante protocol for audio distribution. Both of these brands allow connections of brethren interfaces (AVB or Dante) using CAT5. When this happens the units 'handshake' and the respective ASIO driver is now aware and the additional channels are present in the Hauptwerk's Audio
Setup channel assignments.
Side note, rumor has it that RME will be adopting the AVB standard.
Danny B.