Vizlib Sankey - Group Nodes by Condition / Expression

[lundgrenmatt]

Hi all

I really like the Vizlib Sankey chart, it renders really beautiful charts.

However, my dataset has too many nodes to really be decipherable.

So, I'm trying to use the 'Group Nodes' feature (see attached .png). How would I write an expression to group the nodes on the left together if they comprise less than 2% of overall sales?

Thanks in advance for your help!!

-Matt