2011 Prius Rear View Cameras Question

[Angel And The Wolf]

I have a back up camera in my Prius, but I want to mount a rear view camera under each outside mirror. I regularly have to enter freeways at such a shallow angle that I can't see what is coming up in the lane I'm entering. I'd like to tie these cameras in to the OEM screen, so that by mounting a pair of micro switches near the turn signal stalk, I can turn on one or the other outside cameras by using the turn signal, but I don't know the logistics of tieing in to the display so that it will show the image from activated camera as it does the back up camera when it is activated. Anyone have experience?
BTW, the screens that come with most of these systems show those pesky guide lines, and I don't want them.
Also, I don't want to clutter up the dash with monitors.

[redpoint5]

My Acura has inputs for video on the DVD nav player. It displays whenever a signal is active. I tapped the reverse lights to supply power to the camera, which then sends the signal to the DVD player, which is then displayed.

No idea how the Prius is configured, but that would be the basic principle. The turn signal switch would connect a camera to power, which would then feed into the display input.

...easier to just put blind spot mirrors on the regular mirrors.