Most services seem to have a mandatory level of spam filtering.
robscovell: Hosting it ourselves is one option we are looking at although we would prefer not to. If there proves not to be a service that provides what we want, we will go that way.
robscovell: Yep, that's my concern. We have had some very important emails bounce due to false positives from legitimate correspondents in China who unfortunately are using poorly configured SMTP servers.