audiofire 12 and 4

[rabbitw]

so, after using an audiofire 4 for a couple years or so, i went out and bought an audiofire 12 to use with my soundcraft 16 channel mixer. and wow - the 12 has noticeably more clarity! (so much more that i feel like maybe i should remix a bunch of stuff.) in case anyone was wondering if there's a difference between the two.. yes there is!

but my question is this: can i connect them both in such a way that i can use both at the same time? so far, i've tried daisy chaining them via firewire with the result that the computer recognizes both units, but you can only select one or the other to use at a time. also, audiofire 4 doesn't have word clock connections, so maybe syncing them isn't possible? i'm not a computer expert, so please excuse any glaring ignorance here. thanks.