Ok my understanding in reading your post and my comprehension of rewire and subhosting is that you have to have one master/host and the rest will be slaves.
In my case I would use Cubase as the host, rewire Live/Reason and via cubase and any midi would have to be sent from cubase via rewire into the slaves.
You can still control channels in the host and slave(s) simultanesouly ie if you had a keyboard for a synth plugin in the host and quneo set to another midi channel and set active in cubase to the slave.
You cannot I believe have two host running concurrently as, in windows, only one host can dominate the asio as any one time.
You may get away with it if you have two soundcards (2 ASIO drivers) and use ASIO4ALL, or try using one asio soundcard for each different host. ASIO4ALL will increase your latency sunstantially. Only way I think you could experiment with to be honest I have never tried.
Of course other option would be to have two laptops/pcs each running a host, each with there own soundcard or using midi/audio over lan software.
I am sure it can be done but maybe not how you initially perceive.
Best of luck.