Group-Value
This property sets the value that makes a Radio-Button control selected.
When the Radio-Button control is displayed, it is selected if the value of the GROUP-VALUE property is the same as the value of the Value property.
When the user selects a Radio-Button control, the value of the Value property is set to the value of the GROUP-VALUE property.
 
Example - Define a radio button in one group and make it the selected in the group
screen section.
...
  03 screen-1-rb-2 Radio-Button
     line 20.6
     column 21.7
     size 10.9 cells 
     lines 5.4 cells 
     id 5
     title "Option 2"
     group 1
     group-value 2
     value 2
     .