7i76e MESA two MPG / or potentiometers or digital spindle speed / feed override.

I have a i Mach PS$ USB MPG pendant running with debian 9 and linuxcnc 2.7 and 7i76e Mesa and I use the 0-10v analog spindle control open loop and that's great... but I also want other external override controls over spindle / feed.

Can I connect two override sources into linuxcnc? I could use a second mpg or a digital signal..

I know that If I had a simple potentiometer and I turned the speed up or down with the mpg pendant that would conflict with the pot... so two mpg would solve that but I want to eventually control the machine spindle with a sort of vision system for quality control.

Thanks,