Philosophers disagree as to what "collective intentionality is. J David Velleman argues that two people having communicated agreement with each other are sharing one intention.
Two people on a bus planning to get off at the same stop can be said to have the same intention, but this itself gives us nothing significant. Although two or more minds might have similar intentions at some point in their lives, in each mind the context within which that point exists can be quite dissimilar. The world turns on a lot of conflicting intentionality and inefficient communication. "Collective intentionality" has no value as a concept for sociology or for history