How does group promotion help in this situation? Can you explain how that will do the job?But we can achieve this with workarounds using group promotion + Badges conditionals. Is more manual in the beginning to set the things up, but well, will do the job.
I tend to use the Badges for more "permanent" achievements, but would be great to have a more automated way on "temporary" achievements.
Now That Ive got your attention:
This release contains new functions that should be fully tested, take a full backup before installing on a production site. Optimally try it out on a test site that is a replication of your live site before installing on the live site. It has had limited testing.