Yes it is hold on the channel and press enter. Edit current channel and press enter. Scroll down to set audio type select analog only and then select set lockout.
Be sure to mirror that change in Sentinel by either reading the scanner into Sentinel, or editing the Favorites list that the frequency is in. To modify in Sentinel, open the Favorites editor, selecting the list to change.
In the editor, open the system & department the frequency is in.
Click on the "Audio Option" for the frequency. In the poop-up menu, where you'd choose analog or digital, and set a PL or DCS code, click the check box under the PL/DCS setting drop down to lock out the specific one you want to lock out,