Tux Plot has this ability already.
It will plot in order Black. Red, Green, Blue, Cyan, Magenta, Yellow stroke/outline colors.
For example:
I have a sheet of silver mounted in my engraver and I want to drill holes, cut out design sections etc. then cut the perimeter of each silver earring after the internal cuts and drill holes, I simply use in Inkscape the line colors that Tux Plot cuts in order leaving the perimeter cut to something like magenta (last color Tux Plot in this particular job).
This applies to any cutting device Tux Plot will use, vinyl cutter, cnc machine, engraver etc.
Search youtube for Tux Plot , there is a video on "nested cuts" showing this simple cut order.