To make it fully automatic, so that the graphic & the numbers change with the scale? I beleve so.
To make it semi-automatic, so that the grpahic changes automatically with the scale, but you have to switch the numbers? Not at all. You make one, you make it parametric, and then you make types; one type for each scale. Or you do what I did, and just make the numbers based off of a formula, so you change one and the others fill themselves out automatically, so that you only need edit the legend once when you change a scale...