Hi @jasbro. Depending on your setup, you may or may not actually be able to use more than one KinectV2 per computer. If you're on Windows using Microsoft's SDK (via either the ofxKinectForWindows2 addon or directly), they only support one sensor per machine. I'm working around this by streaming the depth image from one machine to another using ofxZmq which wraps ZeroMQ.
Ironically, on the Mac side you can use multiple Kinects via the ofxMultiKinectV2 addon which uses libfreenect2. I believe libfreenect2 is cross-platform, though the addon is only supported on OSX at the moment. I'm sure either of these projects would appreciate help! With this approach you can get access to the camera streams (color, depth, IR), and registration between depth & color space, but none of the Microsoft SDK features are available, such as the BodyIndex stream, skeletons/joints, etc.
Hope that helps!