Door Latch problems of the 2004 Hyundai Santa Fe

Mainly the passenger side rear door and once in awhile the driver side rear door will lock automatically and the rest of the other doors remain unlocked. I can not get the door unlocked unless I use the electronic key. However, I have to first lock all the doors and unlock them for this to unlock. The door does not lock everytime, but it happens enough that I am very worried. Luckily, there has only been a few "emergency" situations that I had to quickly get to my son and I was unable to get there because the door locked. He threw up one time and started choking, I had to go through the passenger side and hop the seat. Fortunately, I was fast enough and he was ok. If I got into an accident I would not be able to get my son to safety because I could not get the door opened. I have 3 children at times in the car and a handy capped father who has to sit on that side. I am very concerned on the safety of my child and family members. I have brought this to the attention of the dealer ship I purchased my vehicle from since day one, on uncountable amount of times and I kept getting told, there is nothing they can do about this. I had know idea what to do as nobody was helpful. I wanted to buy a new car, but I can not afford it. My son got the "cars" movie for christmas and within it was this "brochure" and I found this site. Please help.