change caption numeric fields

I have a form with at least 2 radio buttons named type1 and type2 and on 2 different pages 2 numeric fields NF[0] and NF[1], the binding of NF is global.
 
if I select the radiobutton type1 then the caption of NF[0] and NF[1] should change into "Type1" and visa versa
 
I have the following javascript text in the change of the radiobuttonlist:
  
if (this.rawValue == 1)
{
xfa.form.form1.test.NF.caption.value.text.value = "type1";
}
else if (this.rawValue == 2)
{
xfa.form.form1.test.NF.caption.value.text.value = "type2";
}
  
this only changes the caption of NF[0], how do I change the caption of NF[1]??
 
best wishes
Simone