i thought about it, but i have some filters like service: streaming media, peer-to-peer, http, File Sharing, Remote Access, IP Protocols, Web Browsing i t.e (~ 200 filters) and if i calculate the top domains in the script,i couldn't to filter it.
Create three rank fields in the data - RankConnections, RankBytesIn, and RankBytesOut - integer value for each domain. Now, if you don't have selections, your top by RankConnections will be 1 to 20. If you make selections, it could be anything (e.g. 120,500,666,... 5215045) - but still sortable without dynamic rank calculations.