Gtk.RadioButton.prototype.set_group

function set_group(group:[Gtk.RadioButton]):void {
    // Gjs wrapper for gtk_radio_button_set_group()
}

Sets a Gtk.RadioButton's group. It should be noted that this does not change the layout of your interface in any way, so if you are changing the group, it is likely you will need to re-arrange the user interface to reflect these changes.