Hi Andreas,
Thanks for providing more details. Most of the datasets functionality available in the Fusion UI is also available via API. Re, group management: You are able to list, create and delete groups via the API. (Refer here for documentation.) This excludes group update -- the method for update in the API is to create a new group > add old members > delete old group.
Re, access control for subsets of datasets: this is an enhancement area that we’ve noted, and I’ll add Statnett’s use case to our product feedback repository. Currently, the workaround is to fragment the dataset; however, we don’t recommend this as it increases complexity and administration.
I hope this answers your questions!