java - Java - Inside a GUI class, I want to display another GUI, how do I do it?

Question

I have a class called HotelMenu, which is called by my Main class. HotelMenu is a GUI which shows a hotel menu. Now within HotelMenu, there are two options for which I want a GUI to be displayed when add or view buttons are clicked.

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class HotelMenu extends JFrame implements ActionListener{
    // I have frame dimension constants here

public HotelMenu() {
    // this is where the GUI for HotelMenu is created           
}

public void actionPerformed(ActionEvent event) {
    JButton clickedButton = (JButton) event.getSource();
    if (clickedButton == viewBtn) {
        // Want to generate a GUI here
    }
    else if (clickedButton == addBtn) {
        //Want to generate a GUI here
    }    
    else // else it's the Exit button
        setVisible(false); //you can't see me!
        dispose(); // closes the HotelMenu form          
}    

// Maybe I can include methods that generate GUI for 2 buttons here?

}

I want to know if I can write two methods within HotelMenu class that allows me to generate a simple JRadioButton GUI for when addbtn , viewbtn are clicked.

I don't want to create a separate class for these, if possible.