I'm an activist investor believing that a change is in order before this company can move forward.

"And I don't threaten or bluster. I just say what I am going to do and when the moment is right I act, and so do the people with whom I am associated."

Feel free to do whatever you like but personally I've never seen a shareholder successfully sue another shareholder. Have never even heard of it. The reasons why corporations are structured the way they are and shareholders are defined in that relationship in detail is precisely for the purpose of discouraging such lawsuits. Personally, I don't believe it's legally possible for a shareholder to sue another shareholder but I wish you all the luck in the world.