The link below is to a PDF file produced by the Contra Costa Consolidated Fire District (CON Fire) for it's personnel. The bulletin lists the radio talk groups and channels by district and battalion. While it does not give the actual talk group numbers, it does provide a little insight as to what the "Charlie 5" and "Bravo 3" channel names mean, and their uses.
http://www.cccftsoa.org/images/shared/EBRCS/CMM-PP3-Communications Plan and Dispatch Procedures.pdf
http://www.cccftsoa.org/images/shared/EBRCS/CMM-PP3-Communications Plan and Dispatch Procedures.pdf