The information that you need is contained in the HP-1 along with a lot more and that may be the problem. I would suggest that you look into how to make up a Favorites List using the Sentinel software that comes with the scanner. You need to have that installed in any case to keep the HP-1 database updated.
Depending on where you are located (well, where the radio is) you may be monitoring a site that is not carrying the talk groups that you are trying to monitor. If you don't understand that or if the term "affiliation" is foreign to you, please read the
Trunking Basics article in the RR Wiki.
Currently the Fort Bend county public safety agencies are still using the
TxWARN Motorola system. So when considering what to load in a favorites list, you should consider those sites, perhaps avoiding those that might be close enough to being locked on by the scanner but not carrying Ft Bend traffic. In that regard, if you would provide a location we could advise what site(s) you should consider that would be carrying the traffic you want to hear. I realize there are always privacy concerns, so we don't want your address, but if you would provide the closest major intersection, that would be good enough.