The only way I could think this could work, is if an EQ used crossovers to split an audio input, before applying eq to it, but ut doesn't an eq is processing the whole signal, even if it ias only effecting a small range. Otherwise to isolate just that section would require filteing out the other sections, which in itself would effect the tone of what you are eq-ing.
It's a nice idea, but I'm guessing it's a flawed one.
You could always try by setting high and low pass, to create a band pass for the section you want to listen to.