As Shane pointed out look at SAINT classifications.
In this case you have a prop or evar for URL
Define a Sub class for it like URL group as an example.
Then download classification template for given prop/evar.
Using excel pick your desired urls(in key column) then in 2nd column add new grouping.
Upload and wait a few hours next day..
You will then be able to segment , even pull a report-let from GUI on this new Classification. New URLs, edits, can be uploaded in future as needed.
GLTU