An equalizer would just be a multi-bandpass type of filter... I think... it's been a long time since I built speakers and looked at crossovers...
You've got a set of 8 frequencies, which you can boost or attenuate. If they are close enough together, adjacent ones would interact with each other.
Maybe the best way to visualize it is by running Winamp, with it's equalizer. It's a 10-band, and by playing with the sliders, you can see the effects and interactions.
It might be easier visually and conceptually to use an equalizer filter instead of the VST plugin... it's just another filter, so I would expect the performance to be similar...