Reviewers have various tools that are used to identify such areas, and as more are added it is often easier to keep these available in a single location.
MY SUGGESTION, at least for Ontario, is to follow this process
- Determine the location(s) where your cache will be
- Create a full listing OR skeleton shell listing (*) that includes all of the locations as Additional Waypoints
- Send the listing in for review as normal
- Request feedback from your local reviewer
This process will provide you with the GC CODE that many land managers use for tracking. It also aids reviewers in finding your listing and giving you the right information. Lastly it gives you more info, like to any existing proximity issues that you may not be aware of.
Of course, you can approach a land manager first in any of these areas and most already know how to communicate with reviewers. Reviewers, at least in Ontario, expect to see an email of permission come from the land manager as confirmation of awareness.