Listowners  are supposed  to add/dele  users  using the  ADD and  DELETE
commands. Is there  any reason why not to GET  list_name and then delete
the lines of the  users to be deleted or add new lines  with new users,
(except for the reason that it becomes QUIET add/delete) ?
and then simply LSVPUT the file ?
 
/Zvika
 
p.s. I did do what I suggested on my test list, and it seemed to work,
     but I might have missed something.