There is a method to do this in tables:
This is shown in Sheet 4 of the attached in the Forum Post
In the Sankey, however, it becomes necessary for the left graph
which only splits on the lefthand Segment Dimension 1 to also know about the righthand Region Dimension 2.
This causes splitting up of the Segments, defeating some of the purpose of the Sankey.
Please see Sheet 5.
Will keep looking.
254439sankey.twbx 627.0 KB