Owners manual let me to believe that I could configure the car so that grabbing the driver side door handle would unlock all four doors, but I could not find the settings for it on my radio/NAV system display... so I tried this, which worked just fine: get inside car when it is off press and hold simultaneously the lock and unlock buttons on key fob until you hear a series of beeps. I got the idea from this thread (although I never saw anything on my display screen like what the author of this post indicated for their different model Prius). Unlock all 4 doors? | PriusChat
I don't have navigation on our 15 V but if you go through the following menu's you can do the same thing. Press Setup/Vehicle/DoorLock Settings/Select Doors to Unlock and chose All Doors.