How to set group data?

[HmiGuide]

The class Usermanager provides 2 methods getUserData() and setUserData().
While getUserData() can look in both (user & group data) for setUserData() the description does not provide any information how to set group data. 

=> How can I set group data?

Below I added an extraction of the WebIQ docu.

getUserData(key [, lookupIn])

Looks up the given key in user data and group data and returns its value. Lookup location may be specified. User data takes priority over group data.

setUserData(data [, callback])

Modifies user data. Key-, value-pairs with a null-value are removed from the users' data store. KV-pairs not included in data are left unchanged. Only primitives may be used as values. Note that changes made to user data are only visible after the callback has been called.

[Thoomas]

Question and answer at onces ... 

[Sgilk]

@Thoomas ,

I still think the question is unanswered. There is no explanation of how to set the group data

[HmiGuide]

It is NOT answered. Please do not mark a question which is not answered as solved.

[webiq-sk · Accepted solution]

Group data can currently only be set in WebIQ Designer, not through the Visuals API.