anchor.diff:     )
      (
         REMOTE_AS asnum = DEC
  -   )? NEWLINE
  -   (
  -      bgp_tail
  -      | nexus_neighbor_address_family
  -      | nexus_neighbor_inherit
  -      | no_shutdown_rb_stanza
  -      | remote_as_bgp_tail
  -   )+
  +   )? NEWLINE nexus_neighbor_rb_stanza_tail [$addressFamilies]
  +;
  +
  +nexus_neighbor_rb_stanza_tail [java.util.Set<String> addressFamilies]
  +locals [boolean active]
  +:
  +{
  +   if (_input.LT(1).getType() == ADDRESS_FAMILY) {
  +      String addressFamilyString = "";
  +      for (int i = 1, currentType = -1; _input.LT(i).getType() != NEWLINE; i++) {
  +         addressFamilyString += " " + _input.LT(i).getText();
  +      }
  +      if ($addressFamilies.contains(addressFamilyString)) {
  +         $active = false;
  +      }
  +      else {
  +         $addressFamilies.add(addressFamilyString);
  +         $active = true;
  +      }
  +   }
  +   else {
  +      $active = true;
  +   }
  +}
  +
  +   (
  +      {$active}?
  +
  +      (
  +         (
  +            bgp_tail
  +            | nexus_neighbor_address_family
  +            | nexus_neighbor_inherit
  +            | no_shutdown_rb_stanza
  +            | remote_as_bgp_tail
  +         ) nexus_neighbor_rb_stanza_tail [$addressFamilies]
  +      )
  +      | //intentional blank
  +
  +   )
   ;
   
   nexus_vrf_rb_stanza
  
positive.code: ;
  
  template_peer_rb_stanza
  :
     TEMPLATE PEER name = VARIABLE NEWLINE
     (
        bgp_tail
        | inherit_peer_session_bgp_tail
        | no_shutdown_rb_stanza
        | remote_as_bgp_tail
        | template_peer_address_family
     )*
  ;
  
  template_peer_session_rb_stanza
  
negative.code: ;
  
  nexus_neighbor_rb_stanza
  locals [java.util.Set<String> addressFamilies]
  @init {$addressFamilies = new java.util.HashSet<String>();}
  :
     NEIGHBOR
     (
  