My solution to simplify the process....Star Wars figurines. I'd like to say I robbed them from an innocent child but I did not. They're mine, from my personal collection, so there.
I labeled a figuring for each character in the scene and made a simple sketch of the rooms the fighting took place. With this high tech strategy I could keep track of who is fighting who and where they are. As my characters moved across the page I moved them on my sketch. I could then make sure I didn't have the same character fighting in two places at once.
I know this is may or may not be the most effective method but it worked for me. If you have a method that works for you let me know. I'm always on the look out for new tools of the trade. May the force be with you.