If you're sticking with the Airport Extreme ecosystem, QuickerTek would like to show you something

[macphanatic]

GuyGene wrote:
My problem is KomKast, Southern Sektor, whose wifi router I must use because we have landline (yes, still need) service with them. It's a lot cheaper than ATT, our only other option. So, even though I have a heap of AirPort Base Stations, I still have to use theirs.

You should be able to turn the comcast wifi off. I did on mine. The comcast router assigns ip's, but my Airport Extreme provides the wireless access.