Have you talked to any of the parents of these kids? The one and only time some neighborhood kids were teasing our dogs (who were 120# and 140# at the time). The kids were poking with sticks and lunnging toward the fence.
I went straight over and talked to the grandparent who the kids were staying with. I explained I worked hard on training my dogs not to bite but those kids were provoking them and working them up at the fence.
I'm not sure what grandma told the kids, but it didn't happen again.