Suppress line in N-value vs. depth graph

Hello - we plot N-values vs depth on our logs.  I would like to give the user the option to suppress a line between two points.  I was hoping I could do this with a linetype field in the SAMPLE table, but when I added that, and then used the <<SAMPLE.LineType>> as the line type override in the plot, it changed all the connecting lines instead of just the one where I populated that field.  Any ideas how to make this work by each sample?