I'd really like to avoid using translating muxer, only as a last resort. I read on the Arduino Playground that all I have to do is connect each AD0 to a digital output:
"Using more than two MPU-6050 sensors can be achieved by connecting each of the AD0 pins to a separate output of the Arduino.
At this moment (15 July 2014) it is not known if this trick works for the MPU-6050.
Update March 25 2016: This trick is confirmed working nicely using three GY-521 breakouts along with an ESP8266 wifi/microcontroller (NodeMCU)."
(Arduino Playground - MPU-6050)
How is this able to work?