On Sat, 4 Dec 1999 11:10:41 -0600, Barbara Passman <[log in to unmask]>
wrote:

>I think I have seen reference to a sub list
>Is there really a way to do this?

You can use TOPICS: to do this, but it is difficult on discussion 
lists to keep people to the discipline of using the right Topic: word
in their Subject: line.

Sub-lists= is a List Header keyword of a separate (but related) list.  
This is described in detail in Appendix B of the List Owners manual.