That made me think of an interesting idea. No problem is not solvable with some level of indirection!
A review aggregator website where the value of reviews from various sources is weighted by how reliable they are. For example, if there is Yelp, Facebook and Google, it can weight a restaurant 0.7 Yelp, 0.2 Facebook and 0.1 Google.
we do. if you use Google as well as Yelp, every other site on the Internet which mentions the business you are curious about effectively acts as a separate review site.