[CentOS] Fwd: ntp help

Hello

I am trying to sync via NTP locally (since I have no Internet access).
None of the NTP stuff I read on the net seems to work right.  I mean it works fine setting up a client going to something like 0.pool.ntp.org but when I want to make my LInux box a server, and I do an ntpdate to it from another machine,
it says no suitable server found.  I have tried every possible combination of restrict, broadcast, multicast.  Followed directions in the examples but
nothing works.  Also "iptables-save" shows no iptables stuff set at all, so there is no firewall blocking it.

Maybe I could ask my question and someone could tell me how to configure?

There are 4 machines:

1. 10.5.1.50
2. 10.5.0.20 / 192.168.1.100
3. 10.6.1.50
4. 10.6.0.20 / 192.168.1.101

The 10.5s cannot reach the 10.6s (except roundaboutly through the 192
network).  The two 192 machines are connected directly to each other.
You can get back and forth between them

I want to set it up so that, and it doesn't matter which way), one of
the 191.168.1.X machines NTP syncs to the other, and then 
the 10.5.1.50 syncs to 10.5.0.20 and the 10.6.1.20 syncs to 10.6.0.20.
How do I set the ntp.conf files?  Remember there is no external internet
on any of the machines, and the 10.5 machines cannot reach the 10.6 machines and v.v. (except the 10.X.0.20 machines can reach each other through the 192 network).  Also I am not allowed to use the 192 machines as routers for the 10.X.1.50 machines.

Thanks