Side by side 3d 2 cameras or one

found the 3d using two colur but no option for sbs (2 camera rig ) full frame or to use a single larger then needed and clip the offset for left and right. the picture then only needs to render once but split the picture left offset + main for the left frame and the main + right offset. this as an addon or an update to the 3d set.
as i am new to this please email as i am not a forum reader

p.s into local radio