Power BI Sankey (Negative values/dropouts)

[pbi_ds_queries]

Hi all, 

I'm currently trying to use the Microsoft Sankey Visual to display a multi stage Sankey, however between two of the stages, I need to be able to show the volume of people who dropped out between two nodes vs people who moved forwards between those two nodes.

Has anyone ever done this or similar please and can suggest if it will work/how it could work? 

Many thanks,