questions about X3 and Scheme

[hal@ZOHAR.AI.MIT.EDU (Hal Abelson)]

In your message about Scheme standardization, you wrote

     2. ANSI recognizes X3J13 as the technical working group for Lisp in
     the US. Therefore, an IEEE effort would have no standing or voice in
     any ISO work relating to Lisp, which is regarded as including dialects
     such as Scheme.

Could you elaborate on what this means?  In particular, 

   (a) Who regards the X3 effort as including dialects such as Scheme?

   (b) Does your comment imply that there could not be an ISO standard
       for any Lisp dialect other than for Common Lisp?