Monitor distribution between GPU and CPU integrated GPU

I have a setup (primarily for gaming) where my primary monitor is a 240Hz 3440 x 1440 that is plugged into a 4080. I have 2 secondary "average" monitors (60hz refresh rates, 1080P) connected into the integrated GPU on the Intel 13900K. Is this setup going to allow the GPU to focus exclusively on the high refresh rate monitor or does some sharing of processing power happen between the iGPU and GPU. I couldn't figure out a clear answer online.