How to seperate a category volume into family volumes

[evyjh10]

I have used dynamo to get the volume of all structural columns as seen in the picture below. However, I want to separate this into concrete and steel columns, and I am struggling to find the best way to do so.

[Draxl_Andreas]

@evyjh10 ,

you can use groupByKey

KR
Andreas

[evyjh10]

Thanks, that was very helpful!