Connecting two sensors to one analog pin
AO is not "Ay Zero", it's "Ay Oh", and stands for "Analog Output". It means it just sends a varying voltage. It really doesn't care where it's sent to, it just sends it.

It's up to you where you connect that output to. But suffice it to say it wants to be connected to an input that can read an analog signal. And the Arduino has 6 of them.

Which one you connect it to is entirely up to you - you just have to read from that analog input by using the right pin number in analogRead().