Email from Yahoo group marked as spam

OK. Well that deep-6’s my big transition plan. Yahoo! uses Precedence: bulk. We have a club with a lot of VERY-long time Yahoo! users and I’m trying to ween them to something better. I thought temporarily forwarding the Yahoo! traffic into a category they could view on Discourse would make it more palatable for them (I selected Discourse primarily for it’s combined email/web functionality).
Thanks.