Hi,
If you have already a geometry collection that you have created using the fracture editor, you need to create the collection from the source geometry
In Dataflow you can do it this way :
You can share a single Dataflow with many geometry collection, this will work perfectly fine with the the method I describe above using the source geometry
If you still want to use static mesh, in 5.6, you can define an static mesh as an input variable and override its value for each geometry collection using it
You can remove a Dataflow reference from a GeometryCollection by editing the DataflowInstance properties on the Asset Details tab in the Dataflow Editor
There’s no way to get rid of the popup asking for creating or adding a Dataflow
The logic for that is in UAssetDefinition_GeometryCollection::OpenAssets is you compile from source and want to locally change the logic
Hope this helps