No, you can't that I'm aware of. There should be features for moving members though, I believe. I'm sure something like "All members who:" and then having an answer like "have a post count of _ or more" and then you just set that to 2 or something (to leave bots in the default user group, and members with 0 or 1 post only. Then you move them and proceed. I'm not saying there's a feature exactly like that, but I think there is something, dunno, I'd have to see it myself. I think older versions have something like it, I can check in a moment. Though if you can just switch the default user group to a new one, you don't need to move anything. This is a pretty simple method, I'm just not sure of all the details with this specific version.