I would like to group pie charts by a relationship custom field.

At the moment, in the list view, it is possible to group by a relationship custom field. It would be wonderful if you could include this feature in pie charts.

Let me give you an example...

I have a list with expenses (Items, invoice number, relationship custom field "Supplier", etc.).

In that list, I have a list view grouped by the relationship custom field "Supplier".

Now I would like to create, in a dashboard view, a pie chart grouped by the relationship custom field "Supplier" again, just like it is in the list view.