Just to expand on what Ed brought up, there are multiple commands you could use, maybe you would get more out of using a Next Part command CC:113 value 126 followed by CC:113 value 0 to constantly go to the next part.
If you need access to all 6 parts, you can use something called a redirect to change the page on the MIDI Maestro once you press one of the buttons.
You could add part commands to other pages or create a page that redirects out any time you change the part (You can see this in the Aeros 6x6 song controls in the Aeros Default Mode).
Read more about the MIDI Maestro app and MIDI in general in our MIDI Maestro manual! Lot’s of important and useful info to get you going!
Please check out the full list of supported MIDI commands here.
You can also check out this awesome video on the MIDI Maestro by Joe Vitale!
Thanks for the question!