If we're going to be libertarian here, sure, anyone can form any group and hope to attract members to that group. Sol wants to create a new group - fine. Members can join it. But what the practical benefit that would be escapes me. I created the Thriller, Mystery, Suspense group, but I didn't intend for members who joined it to post only in that group. It was meant only for a place for like-minded readers/writers to go for discussions or whatever. As it turned out, the only thing I've seen coming out of these myriad groups I'm associated with is the occasional quiz. Perhaps I should be more active administering my group (and if anyone wants to take it over, let me know), but my focus has been posting and reviewing in the Premium group, where the action was and (so far) is. I'm not privy to all the other groups' activities, but I'm not aware of any that have postings only to that group. That would kind of defeat the purpose of this site, IMO. Sol, though, seems to want postings for like-minded writers confined to this new group and for like-minded reviewers to seek those postings out. I guess we could change the mindset of the site and have all the subgroups serve as a minor league, as it were, where genre postings would first go to the applicable group before advancing, if warranted, to the majors (Premium). I don't know, this edict from on high has a "who cares" quality to it unless Sol is pursuing a radical change in the TNBW model, and this is the first step.
Okay, I just ran a test and you can post to both Premium and Shred at the same time simply by clicking both groups when publishing. As stated earlier, I don't see any need for any groups other than Premium, but I see no need to protest the Shred Group any more than the others since they are all evidently going to be a part of the site unless Sol changes his mind about the group system. Unlikely. You can have your cake and eat it too if you desire to post in both groups. And no one need join nor participate in Shred or any other group to include Premium (for those only in Basic) if they do not wish. Take care. Vern