foehn

You could try making a joke out of it.

Get the biggest, most loud colored super soaker you can find. Rig a strap to it and sling it on your back. Make sure it is full of plain water and pumped up before you get to the school. When you get to the school, slow down like you're tired and unclip and if the kids start to look like they are going to harass you in any way, stop, pull the soaker out and fire away... Make sure you act silly when you do this.

You can't really hurt anyone with a giant squirt gun and the kids may go running before you really squirt any of them, but the next time you go by they'll probably have squirt guns also and you will have a cooling respite in the middle of your interval. Plus you will be able to talk to them more easily and explain why it is not a good idea to throw rocks at people (you especially, because they will know you).

Once you know the kids, you might occaisionally challenge them to a race up the hill. You'll be amazed at how fast kids can go on single-speed bmxs up a hill, but you should be able to out last them. With luck you'll make a lasting good impression