If your idea is to spread loses between two 7805s then you have to connect [input-output]==>[input-output] in series ..
Pin[2] is the reference for the 7805's output, which is fixed at 5V level, and can not be used in any other role ..
Have a look at the attached picture and see how you can "shift" the output voltage of the 7805 so it produces more than 5V - in this example it is roughly 8V ..
Also keep in mind that a standard 7805 regulator needs at least 3V difference between input and output ..
:wink:
IanP