I have multiple boxes which I have been controlling manually so far.

I'd like to automate the control using a PC, but it's sort of pointless for me if I can't control all the boxes independently. The slave mode works fine, but I don't want to send the same instructions to every box.

I know that on the hardware side it should be fine, but can ErosTek's software actually control multiple devices? I don't want to buy the software only to find out that it can't.

Alternatively, is there any other software available which can do this? Maybe there's even a way to do this solely with audio streams that I'm overlooking, although multiple audio outputs from one PC is also a fiddly situation.

As a side complaint, I think it sucks that they charge separately for the software. You'd think they could roll that cost either into the unit or the cable, but oh well. People be people. And no demo version means that I can't even try before buying to see whether it would even work, and I can't trust ErosTek to honour Australian returns law if it turns out not to support it.