My list has done exactly what you want but in an entirely different area.
ELREPAIR-L deals with electronic hardware repair and is set up for
electronic repair professionals only.  All of the other forums on this
topic are uncontrolled and therefore get a lot of hobbyist, student,
consumer discussions and comments.

So we set up ELREPAIR-L strictly for the pros.  We did two things to assure
the qualifications of subscribers.  Subscription is though the owner only
(Subscription = By Owner) and we charge a nominal fee.  The fee is only
$4.00 per month with a two week free trial.  $4.00 is insignificant to a
pro who makes his living at this but it discourages non-pros and I get a
little compensation for my time.  :-)

Works great!

John Bachman, NLOFC


(Acronym: Newbie List Owner First Class - one notch up from NLO)

At 10:26 AM 09/08/97 -0400, you wrote:
>I am in the process of setting up a technical discussion list on hypoglycemia
>(low blood sugar aka idiopathic postrandial syndrome or the "brain needs more
>glucose please") meant for doctors, researchers, educators and persons with
>long term learned experience with this condition. There is an active self
>help list on this subject, but its very nature has kept the professions away.
>Also the self help list has no archiving.
>
>Are any of you experienced in this situation. How to keep the self helpers
>off the list without chasing away experienced folk and the professions, and
>with a minimum of aggravation. Is anyone particularly proud of the way they
>designed there archiving or topic schemes that I could look at?
>
>Thanks for any help.
>It's times like these I'm glad I'm nice to newbies!
>Jon
>
>