Is there a way to block the ones that I haven't programmed?
See page 27 of the MANUAL
using HOLD to monitor an active talk group ID Follow these steps to stop scanning and searching and keep the scanner tuned to a desired ID. 1. Press PAUSE. PAUSE appears and the scanner stays on the current ID. 2. If you want to listen to (and hold) a different ID, use the number keys to enter that ID. 3. Press PSE. ID Hold appears, and then the scanner monitor the ID. 4. Press PAUSE to resume scanning or searching for a data channel. locking out talk group IDs Many municipal and commercial services use trunk systems to transmit signals from such devices as water meter transmitters, door alarms, and traffic signals. Some signals are encrypted, as well, and most are not voice signals. Since all these are assigned IDs just like other users, you may want to lock out reception of these ID signals. The scanner allows that you lock out up to 50 IDs for each trunk scanning bank. If you use all the banks as trunking banks, you can lock out up to 2000 IDs at one time. Note: •If you lock out an ID while searching, it is also locked out of the scan list(s). See “using talk group ID lists.” To lock out an ID, press L/O when the ID appears. The ID is locked out, and the next active ID appears. •When you try to register more than 50 Talk Group ID, ID L/O Full! appears. unlocking a single talk group ID You can check all IDs already locked out. 1. Press FUNC, then press MAN/MENU to open menu mode.