I guess I was looking at the wrong direction as you mentioned that all SiteScopes report to BSM, and thus you need to be able to differentiate them in BSM.
Usually people create individual groups to separate monitors by organisations or locations.
Changing the element of the root name from "SiteScope" to anything else cannot be done.
You can of course create a group direclty underneath SiteScope and call it SIteScope_DataCenter_Chicago or whatever.
Greetings
Siggi