You can’t, entirely. Your reviews will contain nominations from 4 different “buckets”.
You get up to 4 types of reviews:
- Your most recent play area
- Your home location
- Your bonus location (if set)
- Upgraded reviews from a broader area
What you’re talking about are probably coming from that last category. When a review is upgraded, it’s blasted out to a lot of people from further away, in the attempt to get an agreement quicker. It may not be an area connected to you, but it’s close enough that you’re being offered the opportunity to review on it.
For example, in Chicago, IL, I occasionally see things from the southern US. I know I may not know everything about that region, but I review the best I can–I know if I upgrade my own noms, people down there will be given the chance to review my waypoints. It’s part of the social contract of participating in Wayfarer. You can skip them, if you feel it necessary. You get 100 skips a day. But there is no way to filter them out.