I don't think that combo cable will help. Because the GoPro Hero3 adapter would not be able to connect to the 3.5mm female input on the combo cable. That cable runs to mini-usb male. Now if you have a standard 3.5 digital recording splitter adapter cable like this, then you can use that combo cable just fine!
But if you have the Hero3 Adapter cable, then you would have to find a way to convert the mini usb male to a 3.5mm male to input into the TRS female connector on that combo cable. That is getting too complicated.
As I understand it, you are looking to split the headset hero3 adapter cable, like we sell here: but you want to be able to split the mini usb input into the camera so that you can record the audio from the headset AND have the camera plugged into power. Is that correct? Basically 1 male mini-usb split into 2 female mini-usb.
If so, I will have my guys look into this right now, and see if we can come up with a solution. There are 2 issues that I see that we'll have to check. The first is that because the intercom system feeds power to the headset and that is plugged into the cable adapter, we need to make sure that the 5 volts that you will be feeding into the camera from the split power supply won't cause an issue, or any power problems for the camera or the mic in the headset. The second is making sure that there won't be any interference in your camera's audio because of the added forward voltage being pushed through the single mini usb. The reason is, because the mini usb has dedicated pins for power, data, etc. So we have to split that and need to make sure.
I'll get back to you
