2D Cut-Scene Animation: Is there any way to structure them?

Hello my friends! I'm currently working on a complex 2D-Puzzle-Platformer in Unity 5 and I'm animating Cut-Scenes within the Animation Editor. They tend to become quite long, because there are several characters and assets in them... so everything is quite messy and it's hard to find certain keyframes sometimes. Now the question: Is there any way of structuring (as marking or grouping things in the animation editor) your animation or are there any good tools/plugins?

Thank you very much in advance!