Android : Extract RelativeLayout from a xml file as a view

I have an xml file containing a RelativeLayout. From an activity which has other xml file associated, I want to extract from the first xml file this RelativeLayout, to use his children. How can I access that thing and store it into a view? I want to call a method using as a parameter this RelativeLayout...(the first xml file is used to fill a Listview). I hope I made myself clear. Thank you a lot for your help!