Use case or problem
In graph view of a tree with depth>=2, if origin node has A,B,C nodes with each of them having multiple children of their own, the children of A are mixed with children of B and C. It will be good if children of A are clustered together and do not mix with B or C. (This is applicable in to a tree where children belong to only one parent group - which is a common case IMO)
Proposed solution
Introduce a new Force that pulls the children of sub-nodes closer.
Current workaround (optional)
Groups - Add color - helps visually separate groups but they are still not clustered