Since he filed it, he's since been beating the drum looking for others to join his fight -- in what I believe is an obvious attempt to get others to foot the bill of HIS lawsuit. I've speculated for some time that his latest move was just a continuation of his previous litigation/challenges to Sirius (which he had the nerve to claim he never did on this very site.) But as you can now see with today's press release, that's exactly what this is -- and it's got his name plastered all over it, with him giving his usual conspiracy theories.
That doesn't mean that the "list" of other shareholders can't get added to the suit -- they very well can be. But I don't believe that Hartleib will allow them to be added until they "pay up" to help "defray the costs". And even if they don't pay to join, any name that is added to the lawsuit needs to be careful. With the loose cannon that is Michael Hartleib as the head of this group, he could very much subject the group to a countersuit for defamation, due to what I believe is libelous claims made by him.