Yes. For instance on the MPX 1 load a program. Then using the PATCH button (see chapter 4 of the User Guide) choose the patch number you want to use (up to 5 per program). Then using the knob and arrow keys select a source (eg. MIDI CC7) then a destination (eg. MstrLevel).

You can have the MPX 1 automatically recognize a MIDI controller as a patch source, as well as assigning its MIDI receive channel to match any controller with the MIDI LEARN function. With SRC selected press OPTIONS with the arrow keys get to the MIDI Learn screen. With this screen displayed simply move any active MIDI controller to automatically assign it as the source for the current patch.