Groups/Sub-groups

Hi, Could someone kindly advise what the situation is with regards to the sub-groups functionality that existed in the previous version of Commons?

Are there any plans to make this functionality available in this or later versions?

Or does it exist already?

If so, is there any documentation on how to make use of it?

There are various threads on this topic but they don't seem to answer the question in a concise manner as there are many questions and replies etc. making the matter more complicated than it is.

I just like to know whether the sub-group functionality coming, is already here or isn't planned to be implemented at all.

And if it is already here, how do we use it?

Many thanks for your response in advance.

Regards