I can’t say I’m aware of anything specific that does this, but I know we’ve done this sort of thing with custom plugins in the past. So that would be an option.
Have you looked into this:
Like this: https://meta.discourse.org/g
As long as you set up SSO between Discourse and WordPress, you can put in some hooks to assign and remove Discourse group access and link those two.
Do you have an idea of how you want this linked?
I’d be happy to jump on a call and work through all of this with you and get you an estimate. You can catch me at hello@procourse.co.