Hey southcast,
You can use either the free version or Pro version to display feeds from multiple public groups, you would just set the group ID directly in the shortcode like so;
Feed 1: [custom-facebook-feed]
Feed 2: [custom-facebook-feed id=1234567890]
Feed 3: [custom-facebook-feed id=0987654321]
This will display 3 separate feeds on your page, each one showing posts from a different group.
If you want all of the posts to be in the same feed, mixed together and ordered by date, then you’d need the Pro version along with our Multifeed extension.
Let me know whether that answers your question, or whether you have any others.
I hope you’re having a good week.
John