First: As someone said above range is additive. Whatever the individual object's range is set at, (site, talkgroup or conv freq.) is the estimated range of it's coverage in RR. When you ADD anything above 0 (zero) to your profile's range, it adds this to the objects range. Remember, this is global - it adds this to every object.
The way to have much more precise scanning is via favorites lists. In FLs, not only do you put in the objects you want to scan, but you can set the object's range individually, or just use what is in RR..
Then, there are
rectangles. The default ranges are circles (the info in RR) - overlapping circles. You can (I did) build rectangles representing borders of states / counties / cities, etc. You can have multiple rectangles if needed to represent borders that are not completely square / rectangle.
I build my favorite lists by location, grouping cities that are adjacent to each other in the same FL. Then, with a range of 0 (zero) I have a radio that switches to objects I want to monitor in JUST that area.
This takes work, but it will do what you are asking.
https://bboxfinder.com/
Use the tools on the left to draw a box. Then use the lat/long info to put in Sentinel for your rectangles.
There are other on-line tools - Google "Bounding box tool"
bounding box tool - Google Search
Bounding Box Tool: Metadata Enrichment for Catalogue Records by Visually Selecting Geographic Coordinates (Latitude / Longitude) for Maps
This one, you can just put in the object (state / city / etc) and get a bounding box.