How to bring parents and sibling to the USA at the same time?

You are right...it is confusing and frustrating. You really need an immigration lawyer. Also , this is not a travel question , it is an immigration question. Yahoo answers has a section on Immigration under the section on Politics and Government. There are people in that section who are very knowledgeable and may be able to help you. I just got reported and got a violation a couple of days ago, because I gave this kind of information to someone. Beats me why. I am sincerely trying to help you by telling you who may know the information about Immigration that you need to know.