You mean that you have 2 different networks and you cannot put the camera and DVR into the same network segment, which occurs to me first to add the Ip channel to the DVR, then you could open ports for the Hikvision Camera and link it remotely. in your dvr .. obviously you should use the public IP of the network where the Hikvision camera is ..
Cheers..
https://www.youtube.com/watch?v=yLoi2igR-wE