We have a stacked bar-line chart created in prd. Need to know how following can be achieved in PRD;

For a stacked bar line combo chart, using tooltip-formula, we are able to get Bar Chart's category key values and measure values on hover using "chart::category-key" and "chart::value" in tooltip formula. But we are not able to get line chart's data point values(i.e. line chart's measure value) on hover.
How do we have it ?
Can anyone please tell us what is the post processing script that can be used for this ?