>This seems most promising, but I'm not sure how to put it in.  I found
"Filter"  under access control in the configuration wizard, and this
information:
  :
>Could you elaborate on how and where to put int the content filter?  And
where the messages following it part of the filter, on the product of the
filter?

The Filter= keyword has to do with blocking sources of email. Content
filters are in a template rather than a list keyword.

I really suggest you read up on this in the List Owner's Manual before
trying it. The manual is available at
   http://www.lsoft.com/resources/manuals.asp

Subsection 2.16 covers content filters, but I also recommend a look at
section 9 on templates in general.

Hal Keen