Combining two USB interfaces to use as one USB interface???

[J.craig]

I have gotten myself into some trouble. I have two USB interfaces, and have tried to aggregate them with audio/midi setup in Mac. Neither of the interfaces show up in the aggregate window. I've tried everything except rebuilding the drivers of the two to force aggregate them. First, would rebuilding the drivers even be possible? And secondly, is there and external interface I could use for the purpose of using all inputs on both devices through one USB interface? I'm getting to a point where I believe I'm stuck with two separate interfaces. Currently I'm using one interface to record all 12 channels of drums on my laptop, and running a stereo track of drums into my second interface (which is connected to my desktop) with the rest of my inputs, just to be able to sync the drums and everything else up in one computer. It's becoming more of a headache than I thought it would be. I can line everything up but would much rather have all the inputs combined as one interface. So, does anyone know of such a device? Like a USB patch bay or something. Thanks everyone.