If we install one keypad for 2 doors - will BOTH doors will open each time we enter the pin? Or can we assign multiple pin #'s, one for each door?

Both doors will not open at the same time. You will just have one pin number, but you will push the number 1 or 2 after the pin to say which door you would want to open. (1- for whichever you program as door one, and 2-for whichever you program as door two). For example, if your pin number is 1234, and you want to open door number one, you would enter 1-2-3-4, then press the up down arrow, then hit the number 1. This will only open door one, and door two will remain closed.