Session Monitor tracking of calls with specific prefix in the "To" header

Hello,

I'm trying to track the quantity and call detail of inbound calls to certain prefixs in the "To" header on inbound calls.  For example, we have numerous lines of business and we have them divided by DNIS ranges (199001xxxx, 199002xxxx, etc).  Toll Free calls from the carrier show the dialed Toll Free number in the Request URI but show the actual DNIS digits in the "To" header.   Currently we have Prefix Tags defined for the various ranges and can pull overall volume to these prefixes.  We want to go a step further and report of the amount of successful vs