guest network

I have a WLAN network with 8 Airport Extreme Base Stations 3rd...5th generation.

The WLAN is stable.

Now i wanted to add the guest-network-function to the whole network.

In our network, there is a Mac Pro Server running OS X 10.6.8 who is acting as a DNS-server.

I did activate a guest network, setting one airport extreme in NAT mode. All other AEBS are in bridge mode.

The guest network seems only to be active around this single AEBS.

Is there any useable setup guide fpr guest networks?