Wow, tough one. I think your only hope is to try to poke the remaining tip out of the hole from the other side. The schematic blowup I have kinda suggests the there may be access from within the main bore directly beneath it, but even so, you'll have to come up with a very small diameter, and very stiff tool, like a 90 degree ended dental pick maybe? to have any hope of pushing it out. What you may be left with though is a hole that may not perform like the original hole if its too deformed. Even if you drill them out with a small wire drill bit, it may require some welding up and re-drilling with the right size, and in just the right spot. At the very very least, you'll have to make all 6 behave the same way! That's step two, after you extract those tips. Good luck