helpful: your arguments really dont add up there. Membership of a few relevant, tightly targeted and moderated mailing lists, is preferable to the plowing through the vast quantity of ranting, off topic rambling and general noise on the newsgroups. Especially as they are frequented by a few individuals whos only remaining connection with RISC OS is to get on the wick of those who still use it.
Your problem is easily solved by routing all mailing list traffic through a different POP3 mail box. If your ISP doesn't offer this facilty, theres plenty of free accounts you can create, then then collect from them seperately.