Hi sheguitarplayer,
To add to what Nick said, it is possible to have one master pedal and two slaves connected in series via MIDI. The master has the expression pedal physically plugged into it, and needs to have its MIDI output set to XMT with EXP sent over a MIDI CC of your choice. The middle slave in the chain should have it's MIDI output set to THRU, and both slaves need to be set to map the MIDI CC to EXP.
Using the XMT MAP on the master and RCV MAP on the slaves you should also be able to use the master to change presets via MIDI Program Change on the two slaves. You can map your own presets any way you like. The expression pedal assignments will be still be locally applied on a per preset basis.
I do this in my personal setup, and use the Pitchfactor as the master MIDI controller. I only have one expression pedal on my board (plugged into the PF) and find that this setup works very well. If you search the forums for this topic or something like "expression pedal over MIDI," you'll find some detailed instructions on how to set this up that I wrote a year or so ago.
-Russ
