Adding radiobutton within radiobutton like parent-child sub menu andfood

Question

Multiple and parent-subchild radio buttons. eg

○Radiobutton1  

         ○Subradiobutton1-1

         ○Subradiobutton1-2  

○Radiobutton2    
         ○Subradiobutton2-1  
        ○Subradiobutton2-2    

How can i implement in java activity android