Not much you can do. A show will either have a seriesId, or not. You can not make a new one up for a series, it must be known to the TiVo (via guide data). You have a couple of options/work-arounds. First, you could choose to avoid using seriesId for those shows without seriesId's, and have them not group. Secondly, you could choose a seriesId for a show that DOES have a seriesId (perhaps one that's similarly named) and group your shows that way.