Mails from list after posting on Usenet

I'm getting all sorts of unwanted e-mail ("stalled post", vacation
messages) after posting to the comp.database.postgresql.* Usenet
newsgroups. This is probably caused by a Usenet->list gateway that
someone is running.

Can that someone please stop doing that this way? Posters on Usenet
never asked for distribution via mailing lists.

TIA,
René Pijlman