All the following should have "4 team members required" :http://coh.redtomax.com/story_arcs/detail.php?id=7 (sky raiders)http://coh.redtomax.com/story_arcs/detail.php?id=8 (freakshow)http://coh.redtomax.com/story_arcs/detail.php?id=14 (Rikti)http://cov.redtomax.com/story_arcs/detail.php?id=455 (1st Thorn Tree)http://cov.redtomax.com/story_arcs/detail.php?id=412 (2nd Thorn Tree)The 3rd Thorn Tree Respec Trial page doesn't exist, so probably a moot point there.