Imagine 6 cameras, 2 on each coordinate axis facing each other. This is what I try to achieve.
However when I first added 6 cameras, chose the first, clicked onto numpad 1 to get into frontview and ctrl + alt + 0, this camera indeed aligned well, but when I chose the second camera and tried to position it somewhere else by ctrl + alt + 0 , the first camera got aligned again, not the second how I expected.