Jay wrote:

Yes that I'm OK with but what I'd like to do is stop these cross-posted
messages ever arriving in the first place.

"Hamster" (used with OE or any newsreader) will do exactly that.

http://www.tglsoft.de/misc/hamster_en.htm

Not easy to set up but well worth it - it can do all sorts :-) I've been
using it for a long time and wouldn't be without it.
--
Regards,

Trøy the Black Lab.