It can be an issue of too much, too close, too soon. Instead of holding baby while you go through hugs and greetings, find a safe place for her to be and do hugs with grandma and others in front of her about 3ft away. This is a phase and she'll be able to participate eventually, but for now give her extra space and let her watch your good example. Let her go to them when she's feeling more confident. Some kids take about an hour to sort of "warm up" at family events, especially at an unfamiliar house.
My 19 month old used to do this 🙃 it was bad when she was around 1 then got better and then she did it again from like 14-16 months. It’s getting better now thankfully. I just let her take her time warming up to them and they give her space but also talk to her and show her toys they have. It just takes time but I feel for you bc it is so embarrassing 🙃 but it will get better just give it time 💗