iPhone: Positioning Multiple UITextFields When Keyboard is Shown and Orientation Changes

Question

I have a view that contains 10 UITextFields created programatically. I want the following behavior:

1. When I click on a particular UITextField, the keyboard should hide all the text fields which are visually below the selected text field.
2. If I have a text field selected and change the device orientation, the text field and the keyboard should both rotate to the proper orientation without the text field losing the selection focus.
3. I need to control whether the return key in the keyboard is active.

How do I manage these text fields to get these behaviors.