I believe three levels is all you can go.
The ALL NODES views are networkwide, meaning any changes are appied to all users.
However, I have an ALL NODES view copied for a seperate user-group working in a single state (U.S.) and made a SQL filter in that view to prevent them seeing 'all'. They only see their nodes. I would think you could some somthing similar then use your Custom Properties for that user-group's nodes to build on those three levels.
There again, I think a node could belong to more than one group if you made an SQL filter to include rather than exclude it.
I have their views restricted to their nodes/servers. Problem is they want to see things organized by what website each server belongs to and if it is a web server vs sql server etc. I have the All Nodes view set up for the full admin view of site location, device type. I was hoping to be able to give them a different type of grouping.