In addition to my comment earlier I believe the first thing you need to figure out is if your horse is doing it out of fear or being a total brat. I’ve had both honestly. Typically it is a horse that has been harshly treated and needs confidence but occasionally you get one horse who just want his buddy RIGHT NOW! So is say access the situation then handle it safely either through soothing her and rewarding good behavior (doesn’t have to be treats! It can be as simple as a change in voice tone or a nice pat/scratch just to get the point across she was good.) or by making her mind. Either way, make sure you make your discipline and reward very different so she knows if she’s doing good or bad. If she’s very new to you more then likely she hasn’t learned to trust you yet and she wants her friends with her as support but once she gets to the point of trusting you she needs to know that you will not hurt her and she needs to listen to you. Horses are too big to let them walk all over you. I’m not saying you need to beat them but honestly if you don’t show them who’s boss they will probably end up hurting you and pushing you around. In conclusion, take things slow, be careful, try to get to the bottom line of this problem whether it’s because her tummy hurts and added stress makes her uncomfortable so she’s trying to tell you or because she is scared you’re going to hurt her in the scary cross ties, whatever it maybe be careful and I hope you get it figured out!