For example, let's just say that your restraint OIS is 11111 and your activity OIS is 22222. Then your VGR could look something like:
EDIT,IF,,myRadio,EQ,"restraint",THEN
EDIT,SET,,orderstring,CAT,"@LOAD_ORDER=OIS=11111"
EDIT,IF,,myRadio,NE,"restraint",THEN
EDIT,SET,,orderstring,CAT,"@LOAD_ORDER=OIS=22222^^^53=`myRadio"
That way, you have the either-or functionality of the radio button but the ability to choose between two orders.