Is there a way to cause data value points to take on attributes such as
bold, italic or color set at the table from which they are derived?

For example, suppose I was charting hits at several web sites as
function of time, and the some characteristic of the site was being
altered back and forth (say font "A" and font "B") as part of
an experiment.

I can easily produce a line graph x=hits y=time for the various sites,
but these is no way to visualize which condition (A or B) was in effect
at each data value point.

I'd like to be able to display the portion of each line connecting
the points with a characteristic unique to condition A or B, or display
a characteristic for each data value point, or display attributes for
the ticks on the Y axis, or shade the chart above them, or put a second
label on the Y axis, reflecting the A or B condition at that tic, or
identify the A or B condition in some other way.

Any suggestions?