Separating power depending on voltage
I'm not aware of any such component. Perhaps you could build a circuit that does this, but I don't think you need one.

You could look at TVS diodes, which will conduct current when the voltage is above a certain amount. By connecting one between each data wire and the ground wire, if the voltage goes too high, current will flow to ground which causes the voltage to decrease. Whether it will work well enough to protect the computer, I can't say.

The energy in the voltage pulse will be absorbed by the diode, so (depending on what sort of quality you need for your project) you should also work out whether there is a risk of overheating. If there is a risk of overheating, then you could include some circuit to turn off the USB power for a while after a voltage spike is detected, so the USB killer can't keep sending pulses.