I'm guessing you're referring to the Google Reviews obtainable via the
MyBusiness API, rather than the
Maps API which is limited to the five latest reviews, to the best of my knowledge as this may have changed.
I would recommend the Business API as it lets you select what to order by and put limits... and if you you specified embedding individual reviews via a provided script. MyBusiness API does let you select individual reviews,
like so, but I'm not familiar with Facebook's way of doing reviews, so if you could explain that a little more I might be able to help further.