Toggle XInput system on/off in c++?

I have a game which allows up to 8 players to play on a local machine. The problem is XInput that UE4 uses only detects and uses the first 4 x360 controllers.
I have implemented support for non x360 controllers using SDL2.
Now, I want to disable the ue4 XInput system and exclusively use SDL2 in the situation where i can see there are more than 4 x360 controllers.

Does UE4 currently have a way to turn the XInput system on and off in C++?

IF not, where is the best place for me to modify the engine to add support for this?

I modified the engine to add support for this, is there some way I can try to get these changes pushed back into the ue4 engine?

Would you please show the url of your repository?
I think I may need this.