I have a similar Panasonic phone system here, although I am using a LinkSys WAP instead of a Netgear.
I do not have a problem with interference between the two, but I attribute that to luck more than anything else.
The Panasonic uses FHSS (Frequency-Hopping Spread Spectrum) to "hop" between all available channels. I do not believe that it is possible to limit the Panasonic to a smaller portion of the 2.4Ghz band.
The
Operating Instructions: Model No. KX-TG2700S manual seems to support that theory.
You might call the tech support number for your phone and ask them to confirm or deny this. That number is (800)211-7262.
Alternatively, you might just move the WAP further away from the phones. My WAP is about 20' away from the nearest phone.