How to check in code if a user has clicked 'Join Community'

Hi,
Is there any way to check in code if the user has clicked the ‘Join Community’ button. The Join Community feature is described here: https://support.wix.com/en/article/becoming-a-forum-member-and-joining-the-forum-community

It would be nice to see this field in the privatememberData collection so it can easily be checked.

I need to know if a user has joined or left the community so I can include or exclude him/her from my own overview pages.

Kind regards.