Hey Hafgren,
This is indeed a solid way of doing it, you will have to test a lot though because I have not seen anyone do it in Unreal yet 
I have done some tests myself and my frame-rate only drops when I have 150+ advanced individual AI’s running around 
You should take a look at this link: https://software.intel.com/en-us/articles/designing-artificial-intelligence-for-games-part-1/
There is also something described like a ‘commander’ AI leading other AI’s like you are describing.
Good luck with your project, I am looking foreward to the results!
Elias