XF 2.1 Changing usergroup after 10 posts

[Jon12345]

I have a Registered Users usergroup for any new people joining my forum. But because of poll spam, I need to set up a probationary group, where they stay for 10 posts. After their 10th post, they get transferred to the Registered group.

How do I get it to auto transfer groups after 10 posts?

 

[Masetrix]

Setup
/admin.php?user-group-promotions/

 

[Jon12345]

Thank you!