Multiple Sound Cards total 24ch

[Rithem]

Hi dear people,

I run Mytek ADDA 192 (8ch) over firewire on a Mac Pro (PT9 Native). Works perfectly.

Now Yamaha makes a firewire "sound card" for Motif Xs and Xf, and it works like a sound card sending 16 mono channels over firewire. This would mean
a huge lot to me, if I could track all synths SIMULTANEOSLY WHILE tracking audio with the mytek. SO my question is / does anybody know:

Is there a way to choose TWO separate devices in I/O settings?

Best, Jan