When you use the {JFBCComments ..} easy-tag, you can specify the href (URL) of the page that the comments are meant to be for. Since each review should have a page of it's own (even if you're not really using it), when you add the easy-tag, you'll just need to use that unique URL. That will make each comment box unique, even if displayed on the same page as other comment boxes.
The Easy-tags have a full description of options on the following page:
www.sourcecoast.com/jfbconnect/docs/conf...ocial-content-plugin
That information is also available within the extension in the Social Configuration -> Examples tab.
Finally, no, there is no way to restrict commenting to just your members. Unfortunately, Facebook allows any Facebook users to comment, and there isn't currently a way to restrict that.
Hope that answers all your questions, but if you have more, just let us know,
Alex