Multiple Kinects v2 on a Single PC
From iPi Docs
iPi Recorder supports multiple Kinects v2 on a single PC using libfreenect2 instead of Microsoft Kinect SDK v2.
To use this, first you need to enable corresponding camera type in iPi Recorder. Open Camera Types panel and hit ENABLE next to Microsoft Kinect 2 (libfreenect2). Alternatively, open Add Device dropdown and select Kinect 2 for Windows (multiple sensors per PC).