You fellows have been busy while I was working!

Yes, what OG said. Use the Rane as a 2 way crossover.
The bass output of the Rane goes to 2 stereo amps (use a Y cable). These 2 amps power your woofers.

The treble output of the Rane goes to 1 low power stereo amp. That amp drives all 4 horns (2 horns left, 2 horns right). Use L-pads on the horns to match the level of the woofer in the same Valencia cabinet.

You'll want some sort of preamp to drive all this with one volume knob. It goes before the crossover. With all these various volume controls - preamp, crossover, 3 amps, L-Pads, it can get confusing. But don't worry, we can walk you thru it all and help you. If you have or can find a voltmeter that has a low AC scale (about 10V) it will help with setting levels.