M3UA and support for multiple SGs

To whom it may concern:

In reviewing the M3UA RFC with a couple other members of the community,
it would appear that sub-PC routing granularity will not work if
connecting to more than one SG.  Let's take the following example:

      AS1:                    AS2:
     1-1-1  ISUP             1-1-1   SCCP
     +----+                  +----+
     |ASP1|                  |ASP2|
     ++--++                  +++--+
      |  |                    ||
      |  |                    ||
      |  |  +-----------------+|
      |  +--+------------------+-----+
      |     |                  |     |
      |     |                  |     |
    +-+-----+-------+       +--+-----+------+
    |    SG1        |       |    SG2        |
    |   PC = 2-2-2  |       |   PC = 3-3-3  |
    +------+--------+       +-------+-------+
           |                        |
           |                        |

In this case, AS1 has routing keys of DPC=1-1-1, SI=5.  AS2 has RK of
DPC=1-1-1, SI=3.  If, for some reason, ASP1 becomes inaccessible to SG1,
but not SG2, then SG1 might send a UPU for PC=1-1-1, User=ISUP to the
network.  However, this user is still accessible via SG=2.

The same problem might exist if the Rkeys were DPC/OPC rather than
DPC/SI

Couple questions:

1) Does anyone see any problems with this logic?

2) Do you think we should mention this in the new M3UA RFC bis document
(or some other RFC).  If so, I'd be happy to try to work on some wording
with others.  Or is this inherently obvious to all members of the
community and therefore doesn't require mention?

Regards,
Lincoln