JavaFX 2.0 :: Multiple Scene And Passing Variables With FXML Files

Lets say I have a desire to convert and entered value to Centigrade or Fahrenheit and that I have two Radio Buttons to designate the type of conversion with the Answer posted to a TextField on Scene Two from a button click event on Scene One ok Now I would like to convert the value in the TextField on Scene Two to Kelvin and reflect the value on Scene Three in a TextField by clicking a button on Scene Two
 
lets say  I have 4 FXML files sceneONE sceneTWO and scenMain and I created 4 controllers ControllerONE and MasterController

So far I can navigate to the different scens with just the MasterController code below...

BUT because I have two FXML files I can not capture the value in the first FXML file and pass it to the second scene
 
This project is my attempt to adapt the FXML style code from this web site

Switching to Different Screens in JavaFX and FXML | JavaFXTutorials

Which uses this code to switch scenes

    //get reference to the button's stage                stage=(Stage) btnS1.getScene().getWindow();
       //load up OTHER FXML document
       root = FXMLLoader.load(getClass().getResource("ATTwo.fxml"));

But will not permit variable transfer due to scope of variables which reside in two different FXML files
 
public class MasterController implements Initializable{@FXML public Button btnS1;
@FXML public Button btnS2;
@FXML public Label lblS1;
@FXML public Label lblS2;
@FXML public TextField txfS1;
@FXML public TextField txfS2;
@FXML public AnchorPane root;

[Code] .....