Yes you can do that on a K series or any Hik NVR with PoE ports (if I've understood your requirement correctly). You can connect any one of the NVRs PoE ports to a switch (not hub) and run as many individual cameras from it as you have spare capacity on the NVR. This is handy if you've already got a camera in the vicinity of your proposed new one. No downsides as such, but to avoid issues set an IP address and password in the camera first and BEFORE connecting it, change the appropriate channel(s) on the NVR from Plug n Play to manual using the allocated IP address and password