Mark the first channel name in Sentinel and then the last Audio option while holding down shift. One audio option will popup so cancel that before doing the copy command.
Paste into Notepad, or Excel might be easier to handle, and edit the audio options. When done mark all text in Notepad or all cells in Excel that you first pasted in and paste back to the exact same place in Sentinel by marking the top left and bottom right field that you originally copied.
It helps if you first edit Sentinel to a CTCSS and a DCS value so you know how the syntax are supposed to look like.
/Ubbe