Thanksgiving Worries

To say I'm worried about Thanksgiving is kinda like saying Dallas has traffic:  There's a lot more than you really know until you get stuck in it.
I'm not worried about my mother.  We've managed to sort a way to be civil and even enjoy each other's company to an extent.
I'm not worried about my father.  Things are amicable and familial between us.
I'm worried about my middle sister.  There is a deep, pulsating rage directed at her for even existing, let alone having the audacity to be at a family meal and have the desire to talk with me.  I realize that much of this is directed at the traits she has that I dislike (read: see in myself.)  I realize that some of it is directed at her audacity at trying for something "normal" when we were young and rocking the boat.  Some of it is directed at some of the grudges we bear from long ago.  I think there may even be some sibling rivalry for her getting some of the attention I wanted and never asked for by having ADHD needs.  I try to view her as a human being.  I try to view her as another damaged person just trying to make it.  Neither seems to work.  I counsel myself to be patient and "let go and let god." (I think that one infuriates me even more.)
I think it has to do with seeing my "scapegoat," my symbol of everything wrong in the damn family, as a human, not just a bag of faults. I think I offloaded a lot of blame and shame from myself and my parents to her.  To let go of that scapegoat is scary, because that means letting go of old grudges, old blames, old shames, old worried and just being.
I'm not sure.  I know it needs to be done. It's still a really scary rope to let go of and hope there's an airbag at the bottom.