I don't believe you can target Facebook groups and Social Lead Freak, as far as I understand it, would scrape the user IDs of people in the groups whereby you would create a custom audience. But, that is not the purpose of custom audiences on Facebook so they have been shutting down that option. Especially on scraped user IDs. And you will likely be banned if you go that route.
You most likely cannot direct link to ClickBank either. You may get away with it for a few days but eventually they will figure it out.
Guess that only leaves you with one option. And, really, it's the best one.
Another option, instead of doing clicks to website is to start a page. But...I don't know the niche youre after. Not all niches work with pages.
Oh, and here is the social media marketing forum: