Looking for a compatible personal firewall for my C7800

Yikes, thanks for the reply.  I saw a thread that stated not possible.  I hate that I bought this model with a built in modem.  I normally do separate devices.  Your network looks a bit complicated for a home set up.  I just need to block certain connected devices from port 80 and adult stuff from my kid.  I tried keywords in my 7800 but that didn't solve anything.  Plus would love to block the edge browser from the damn xbox, lol.  Kids growing up with computers are such hackers and find tools to get around.  I may have to do what you stated and run the 7800 as a modem only and connect my old wifi router to a small firewall box.