Is it possible to collect historical group membership per agent?
You can see current group membership for every agent using our API.
However, historical group membership for users is not something that can be tracked with the agent interface, the API, or GoodData.
If you wanted to track this, a workaround would be adding tags to the user profile so you could show group membership. Alternatively, you could use our API to pull user membership data and store it externally to track changes over time.