I'll be honest, I only read a couple of the replies, but here's my take - take it for what it's worth.
Facebook is not a marketing platform. It's a networking platform. You have to fundamentally understand that before you start trying to monetize it. Particularly with the changes we've seen already in the last few weeks, and the anticipated changes in the coming months.
Once you grasp that (and I mean, really understand it at a low level) you'll find greater success with Facebook (and any networking platform for that matter).
Now, while this is the "spark notes" version of everything, know that I'm not saying to avoid FB at all. Just use it properly.
If marketing your articles (provided, they're both unique, and interesting) I'd advise to you spend far more time promoting your articles to blogs within your niche - gain the authority there, direct them to your FB group, capture the lead, and monetize.
Just my 3 cents.