oh yeah, thats a proton video- I thought you were refering to rendering out an animation where you render the scene out from the perspective of the first camera, then switch to the perspective of the second a few frames on. If I understand you correctly, what you want is the CCTV shader, which does ship with lightwave.
heres the link
http://members.shaw.ca/LightWavetutorials/texturing.htm
do a search for cctv