While the second film focused on external matters around the characters after they separate. The battles are larger and include more sides. The fellowship is split into three groups. Frodo and Sam are the first group. Then we have Aragorn, Legolas, and Gimli. And finally the last group is Merry and Pippin. Their goal remains the same but they each take a different path to complete it.
On the surface, the battles fought do not connect to one another because the reason behind them is not the same. One is for revenge, another to save lives, and the last to keep the evil at bay. But they do connect because of the Fellowship. They are still working together. Their separate actions bring everyone together to save Middle Earth in the last film.
Join me next week for the last battle in The Return of the King.