Is there still support?

> Is this at all possible?

Not really, unfortunately. At the moment, group reviews are actually stored as activity items, and are necessarily attached to groups. The plugin would have to be substantively rewritten to avoid this. Alternatively, you could attempt to filter out the reviews when viewing group activity streams; this might best be done at the template level, by querying for ‘review’ activity items and then feeding an 'exclude' parameter to bp_has_activities()

Good luck!