The same situation when using multiple of K678 mics. Please note that even if you plug more than one of FIFINE K670 microphones on Mac, there is only one of K670 will be seen. That means you can use only one of them. Check out very useful video below and take the text as the complement. It can’t be any easier to do that with an Apple computer. We roughly categorize the situation into two, Windows and Mac (apologize for those who use the other kinds of system that we still haven’t found the valid and effect method for multiple mics recording).
So what we can do is to aggregate multiple inputs into one. We can’t change the fact that computer or software allows only one input source.