How to process n groups of 500 photos simultaneously?

[zhengshuo1]

As far as I know, the number of photos registered is limited to 500. So I want to know, if the number of photos that I would compare to is more than 500, for example, 8000, then, is there a way to process 16 groups of 500 photos simultaneously? At first, I wanted to use the multi threads to process, however, I found that the class FaceRecognizer2 seems like only to be instantiated once a time.
Is it right? Hope to get your answers.