Thanks Jobeard. Unfortunately, that reads like greek to me! Is this something I should probablly pay a professional for, or can that be simplified (without too much effort on your end) into directions I might be able to follow?
Here is what I have set-up now:
DSL modem > Linksys Router
Out of Linksys router:
1) 4 pcs networked through ethernet cable
2) linksys wireless access point
those are just wiring diagrams.
the only thing to 'configure' is the unique router address and to allow each to be a DHCP server.
AFTER you have Internet access for everyone (wired + wifi), then add encryption to keep your neighbors off your network.
here's how to test for isolation;
1) each system attached to a given router should be able to ping every over system attached to the same router
2) no system on one router should be able to ping a system on the other router.
Ping WHAT and how?
document the ip-address of every system
use run->cmd and then enter ipconfig
the reply is the ip-address of that system
Once you have the addresses of all systems;
in that same CMD prompt window enter
ping aa.bb.cc.dd where aa.bb.cc.dd is the address of
some other system
if you get 'request timed out' then This system
can not reach That one.
if you get Reply from aa.bb.cc.dd ... then This system
can reach That one.