Pre Out on Integrated Split:1st back in 2nd to New

I have a Marantz PM7200 Integrated. I'd like to split the signal from the Pre Out, run the split signal back into the PM7200 and the other to a new amp. The idea is that I can drive my woofers using the PM7200 and and my tweeters/midrange using another (tube) amp. Is this technically feasibly? Will the loudness coming out of my speakers be balanced?
Interesting. Are you talking about bi-amping a full range speaker or do you have a seperate subwoofer? Either way, it seems as if there should be an easier way of getting where you want to be. Assuming you are going into bi-ampable speakers (speakers with two sets of inputs) you could always just use the pre-outs on the Marantz into the tube amp and then connect that to the (unbridged) inputs for the tweeters/midrange on the speakers. Then, you just run direct out of the speaker taps on the Marantz to the woofers -- and the speakers will be bi-amped, with tubes driving the high end and the Marantz driving the bottom. Not sure I understand the point (or the concept, really) of splitting and looping the pre-out back to the Marantz only to send it back out again, unless, of course, using the pre-outs somehow electronically disables the speaker taps for the same channels (and that is a question I can't answer, but I can't imagine why they would have set it up that way). Have I missed something?

As for whether the volume levels to each imput on the speaker will be identical, it's safe to say they won't be -- but that is always the case when you bi-amp stuff with other than identical amps. It might be possible to rectify that by getting some sort of outboard crossover in there someplace, but, with that, we are way beyond the horizons of my knowledge.