[NTG-context] How to define an array of colors in Metafun

Hi all, I have a family of graphs to draw in Metapost and I would like to attribute a different color to each of them according to the value of a certain variable. Assuming that the path mygraph(j) depends on the variable j, which is computed within a lua code and passed to Metapost, I wonder if it is possible to define an array of colors named mycolor, so that I could say draw mygraph(j) withcolor mycolor(j) ; Here the variable j takes integer values (say between 1 and 10), and one would have defined mycolor(1) through mycolor(10). Thanks in advance for any help: Otared K.