Don't you think that your requirement may misleading with the App Store Review Guidelines.
I think your app does violate the "Not enough lasting value" guidelines as you want "app redirect to Google review page" without any user being specified. In this way, your app do not keep sufficient features as it doesn’t offer much functionality or content, basis on that it may not be approved by the App Store Review.
There must be some other way,
As if we specify users before they pay review from the Google review as well as the Yelp review.
For this, we will add a Registration screen and a Login screen on app. And a Web section(JAVA/.net/Php whatever you suggest) to provide manipulation among user details. We will map the app with this backend in way, so that each user can be specified separately.
Another, Integrate Facebook/Twitter login feature to your app: This way people log into your app, Facebook/Twitter can grant permissions to your app so they can place their review easily. Hence they do not need to be registered from the app to place their review, and there also reduce the chances for apple rejection since it will be a massive feature in your app.
Each time the web will calculate the % customer review according to each user. And transfer the rate to app through a realtime updation service (Silent notification).