OK, where are you going to send these three outputs(frequency bands) to for processing? The only way I know to do something like this with what is included in mixcraft is to duplicate the track and then put a low-pass filter on one and a high -pass filter, etc with an EQ or filter. And then you could process each one seperate.
There are plugins that do this such as the Blue Cat Audio plugin.https://www.bluecataudio.com/Products/Product_MB7Mixer/
Maybe someone else on the forum has some other idea, I have never tried to do something like this.