Ask group of radio buttons for checked value

Given the following GUI part:

$Group1 = GUICtrlCreateGroup("Direction of label", 320, 216, 257, 73)
$radDirectionHorizontal = GUICtrlCreateRadio("Horizontal", 328, 240, 113, 17)
$radDirectionVertical = GUICtrlCreateRadio("Vertical", 328, 264, 113, 17)
GUICtrlSetState(-1, $GUI_CHECKED)
GUICtrlCreateGroup("", -99, -99, 1, 1)

.. can I ask the group somehow (perhaps using a UDF) which radio button is selected ?

Something like

$selectedRadio = _RadioGroupGetSelected($Group1)

.. and have index value returned (here, 1 or 2 as last item is checked)

Or do I have to manually loop over each radioctrl ?

Btw: application is for generation of labels in a layout program.