I think we need some guidance from the BDFL about when a series should contain release groups and when it should contain releases, because I'm doing it differently from how I've seen other editors do it. The way I thought about it, series would be of releases when they explicitly cut across release groups, e.g. a label reissuing several albums for an anniversary or, say, re-releases for record day. If the whole release group has to be a part of the series, the series should be at that level. For example, I would have made this a Release Group series: http://musicbrainz.org/series/f6290a3a-8111-44cc-a02a-bef081ab038e but when I've asked others about such examples in edit notes they've said they always make the series at release level in case the release group ends up containing releases that fall outside the series - in many cases I can't see how that could happen. So either there's something I alone am misunderstanding or we need some guidance.