Display custom series in tooltip in Graph panel

I’m using postgres datasource and plotting a line graph using graph panel.
I am plotting 4 series in the graph. At any point, 2 of the series always overlap. Is there a way I can manipulate the hover tooltip to only show the overlapping series?
I can either display single or all series. But I want to display only the overlapping series.
Is there a way to get around it?