Great grandma playing favorites

So I know im about to sound ungrateful or just down right wrong or petty but this is really getting under my skin. So every year we all get together at my mil house. Dhs grandma girls great grandma always plays favorites.. Dhs brother has 3 girls and one step daughter. Great grandma has always been super close to his girls. She barely knows our 2. Well every xmas its the same she will show up with tons of gifts. Im talking at least a good 8+ each for all dh brothers girls. It always really nice stuff like ugg boots or really expensive toys for the other 2 year old. Yet my girls always get one gift and its always something small or a hand me down she had laying around. Last year it was a stuffed bear with animal hair all over it and a jacket way to big for dd1 with the thrift store tag still on it... This year she got my oldest a frozen book ment for a 3 year old. Im talking the cardboard books. Dd1 is 9. My youngest got some plastic bracelets. That's it. All while all the other girls got over the top gifts...She never says hi to my youngest or even acknowledges she's there. She has a wired superstition about red heads and them being the devil. No joke she said this when dd2 was first born.. Its not fair to my girls and my oldest did question why she got a book that was ment for her sisters age and why did the other girls get so much yet her so little. She even questioned if Great grandma liked her. This was on the way back home. I just told her maybe she forgot but really I know its because she doesn't like dh. He was alway the black sheep of the family... It really hurt to hear dd1 say all this. I'm thinking to either say something or just avoid going there on xmas day and doing it the day after with just mil and fil. It will suck because we wont get to see my nieces but I can't keep putting a smile on and acting like what she is doing is okay... Yes I know gifts are gifts not something to be expected but it hurt dd1 feelings this year.... So what would you do? Would you say something or just avoid xmas with her all together yet that means we would miss xmas day with the rest of the family? Or am i being petty and just let it go? Be honest please. Normally I srug this off but dd1 caught on and I hate seeing her hurt. It will only be time till my other dd catches on. I cant keep lying saying she "forgot". Also I've tried to have somewhat of a relationship with her. I invite her to all the girls birthday parties and she never shows. But for my niece's she there early and stays for the birthday.