InfoPath Dev

I'm using cascading dropdown list and I want to refresh each dropdown in the on change event For example: I have two dropdown list, in the first one I have the following options A,B,C in the second one I have D,E,F if I select in the first DropDown option A I want to refresh the second one and so...

Not sure if this can be done but after you complete a form. Lets say you have a drop down list, and it has some values. Can we, overtime, have the data that users input be integrated in to that form so that lets say we are choosing from a field called Vendors which I currently placed only 2 options,...