How do you handle negative family interactions during holiday dinners?

As usual, we are hosting Thanksgiving and, unfortunately, it is never a Norman Rockwell event. Father in law, FIL, divorced MIL after 30 years to marry his childhood sweetheart 20 years ago. Sister in law decided she did not want to be a mother and left husband with young son. She has since married. BIL had fight with FIL and will not come if he is there, nephew has 2 children out of wedlock and the mother is now back with her ex, etc. I know as hosts we are supposed to decide and control who comes into our house and not let others determine the guest list. We never accept an ultimatum, e.g. “I won’t come if he is there.” But, we understand there are hard feelings and the negative vibes are often so thick you can cut it with a knife.
Here’s how we handle it. I make a spreadsheet with the names of invitees across the top and down the sides. The diagram looks like graph paper. I then color in each square with the interaction level. If A will come no matter what and has no problems with anyone, their row and column is all white. If B is fine with everyone else but won’t come if C is there I put a black triangle in the lower left corner of the box. If C won’t come if B is there I fill in the whole square. (mutually exclusive). I work my way down the list filling in the squares as I know it. If this were not so tragic it would be funny.
I found that is was possible to have 2 dinners. A dinner for all the people who have no problems with anyone or are willing to let bygones be bygones, and a second dinner consisting of the leftovers for those who simply cannot face the ones who showed up on the main holiday. If someone can’t fit into both holidays, tough! Happy freaking Thanksgiving!

So, how do you handle similar interactions at your events? What do you do if Aunt Tillie won’t come if Victor shows up with his gay partner of 5 years? What do you do if the second leftover holiday becomes bigger than the first?