Question About SLAVE DNS and named.conf

[Cekke]

Hello
I've got Three DNS. Actually i create the .dns file on DNS1 and update 
named.conf.
On Dns2 and Dns3 i only update the named.conf(and they go on Dns1 (master) 
to take the file)
Question : it's possible to find a Way to update only Dns1?
Dns2 and Dns3 must be (every time) update in named.conf or there's a way to 
auto-update?
tank you very much