I don't believe you can do that. The only thing I can possibly think of is bi-amp'ing with a pair of 585's (not that I'd recommend it, but..)
Using a pair of RCA splitters coming off your pre-amp, you plug in two sets of RCA cables for each channel. Then take both cables from a single channel (left or right) and plug them into a single 585 (i.e. the two left pre-amp out cables goes into left+right channels for left 585 and vice versa.)
As long as your speakers are bi-wire capable you can drive the two different ranges (highs/lows) with the left/right channels from the same amp. You'll also need to make sure you have two sets of speaker wires for each run.
I use to know a guy who preached about the sonic virtues of independently driving the highs/lows of a speaker with a separate amplifier, but I never heard it myself. Maybe ever so slightly, but it wasn't "amazing".
Anyway.. good luck.