Most of us have already used
          some BGP community policy to no-export some routes to some
          where.

          On the majority of IXPs, and most of the Transit Providers,
          the very common community tell to route-servers and routers
          "Please do no-export these routes to that ASN" is:

 -> 0:<TargetASN>

So we could say that this is a
          de-facto standard.

But the Policy equivalent to
          "Please, export these routes only to that ASN" is very varied
          on all the IXPs or Transit Providers.

With that said, now comes some
          questions:

          

          1 - Beyond being a de-facto standard, there is any RFC, Public
          Policy, or something like that, that would define
          0:<TargetASN> as "no-export-to" standard?

2 - What about reserving some
          16-bits ASN to use <ExpOnlyTo>:<TargetASN> as
          "export-only-to" standard?

2.1 - Is important to be 16
          bits, because with (RT) extended communities, any ASN on the
          planet could be the target of that policy.

2.2 - Would be interesting some
          mnemonic number like 1000 / 10000 or so.