DPlot

Is it possible to use a non-continuous or broken scale on the y-axis? I'm making a scatter plot and I have a cluster of data around two y-values with a bunch of empty space in between.

I can see how I can do this using two independent y-axis, but I was wondering if it's supported directly.

No. The only way to do that (and I'm definitely not suggesting this, as it will be very tedious) is to substitute your own labels for the numbers on the Y axis using Text>X,Y Labels, set the number format for Y to "none", and adjust the Y values that are greater than your break point(s) with Edit>Operate on Y and something like Y=if(Y>(some number),Y-(offset),Y).