To try and answer the OP's question. I would look at some of the explanations in each departments "description column". Some, like the Dept of Forestry, say 'east or a city region like Salem'. Try to correspond those to VSP divisions (Forestry's East might encompass Div 1 and 5). Others, like DOT seem to correspond to VSP divisional districts (so the safety patrols and VSP cover the same roads).
Where the real fun begins is trying to associate STARS tower sites to geographical divisions and put control channels to those areas. Really difficult near boundaries (e.g., the Williamsburg site [1/12] is almost to the Div 1 and 5 boundary). As I've traveled 64 from Williamsburg to Richmond, and switched from Div 5 to Div 1 crossing into New Kent County. The CC for Div 1 is still on the Williamsburg tower until I get closer to Richmond.
Too many entered control channels will slow the scanning down trying to find the active one, not having the correct sites programmed for a zone may cause you to miss transmissions.
During my 'stay at home', I played with multi site systems and how to more easily monitor them. Some like NC VIPER or Ohio MARC (where I used to live) with over 200 unique CC's are huge regardless of what I do. However, STARS is pretty easy in the long run.
STARS has 66 sites utilizing around 310 frequencies on those sites. Only 140 or so are designated control channels. 74 of those are duplicates leaving 66 unique CC's to work with. I put those into a single list (csv file) and it has worked reasonably well as I go between VSP divisions. 66 is still a pretty goodly number to deal with and some would not go this route but setup each site (another challenge in doing that) or try to merge some sites to a division.
For my 'home' area, I have a separate STARS system with just local CC's to shorten search time for a control channel. Traveling out of Div 5, I have a statewide FL scanning all 66 control channels for a signal. Drove to Woodbridge last week with no appreciable issues on finding a CC. Ran a Unication G2 and my 436. The Unication fared slightly better reception wise, even with it not switching towers until the current tower signal is gone.
I monitor primarily VSP and the VDOT safety patrols on STARS. Safety, with what seems like a single active TG per division (at least in Div 5) is much more active than VSP, getting calls for flats, debris, as well as providing lane protection at accident scenes.