The previous post (link) had started out with an analysis of the differences between a Facebook Fan Page and a Facebook Group, and based on that analysis, and comparing with your need, you would need to figure out which one is more suitable for your needs. Here is the concluding part of that article:
1. Groups can send messages to their members as long as members are less than 5,000, while Page Admins can send updates to any number of fans
2. You can directly update content from your blogs and other areas such as Twitter by using applications such as RSS, Networked Blogs, etc, while Groups need manual updates – this if you want your blog posts to automatically appear on Facebook, then a Fan Page is the way to go
3. You can promote your Fan Pages through the use of targeted ads, something not possible with Facebook Groups. Through ads, you can get a large number of fans
4. Groups allow a far higher degree of control over who all can join the group or not, including ensuring that members need to be approved before being allowed inside, while the level of control in a Page is far lower
In short, it seems more like that Groups was something that Facebook was supporting earlier, but the focus is now moving over to a Facebook Fan Page being the area that will have a higher focus.
