Question on reply to a list???

[wnpauls @ WIND . WINONA . MSUS . EDU]

I would like a list I have up and running to only allow original post sent
directly to the list name.  (The usual posts).  I would like to prevent
users from replying to any posts on the this particular list.  I am
running about 20 lists.

Any ideas?  

Thanks,

Paul Schumacher
Winona State University
Computer Science Departmentn