There is nothing that i know of that will do this.
However if you wish to throttle down Seti when a certain temperature is reached, then you should be thinking about better cooling. Seti will run your CPU @ 100% use, and therefore the max temp you will reach. If this is too high for your liking, then when you run games or other apps, then you will still "overheat" when running those.
What is your current cooling setup, we may be able to help you tweak this 🙂
Confused