Opening the backseat doors

I rarely drive with anyone else in my 2004 Prius, except occasionally one person in the front passenger seat. This week we've had out-of-town guests, with two people in the back seat. When the doors are locked, the front seat passenger can pull on the handle to open the door, but the back seat passengers can't open their doors with the handle until someone in one of the front seats pushes the door unlock button. The child safety locks are _not_ set. I keep getting out of my car and forgetting to push the button to let the back seat passengers open their doors. Is there anything I can do to change this rear door behavior? Thanks.

 

Thanks. I don't know why I didn't see that except I never sit in my back seat. I was looking for a button on the armrest like in the front seats.