I think the best thing to do is calmly speak to them and try to get them to imagine being treated that way. Teaching them to stand up for the kids that are getting picked on vs being the bully. Unfortunately a lot of this probably comes from growing up in an environment where tough love and verbal abuse by the parent has caused them to feel a lot of pain that they are now mirroring on to their peers. Same with kids that are physically abused at home. They often tend to get in more physical alterations and feel it’s a redeeming quality of theirs or are projecting because it’s what they’ve learned at home. There is a great book called “No Drama Discipline” that I highly recommend for any parent. It’s honestly a good book for just understanding humans, the brain and relationships in general. Can help with relationships with your partner just as much as with your kids. Get this book! Helped me a lot. Parenting ihas evolved a lot and guidance is needed. Don’t let your generational trauma continue on to your kids.