low TTL on cache NS

[dave stern]

I have several mailservers running cache-only nameservice to reduce
their
external queries. On occasion, we move hosts from one net to another but
the
Cache-only NS doesn't pick  up the IP change we make on the master NS
despite the mailserver being listed in the named.conf on the master
under
also-notify.

Is there a way to reduce the TTL on cache-only NS to something really
small?

I'm guessing that the Cache-only NS inherits the TTL from the master
anyway
thus making a change to its named.local for a short, default TTL wont
work.

Thinking out loud, I could accomplish the same thing by just having a
cronjob
on the Cache-only NS to reload every hour. OTOH, I doubt this is even a
wise thing to do as
- We generate and push/pull host files nightly so the current file
wouldn't have the
   update anyway
- Reloading frequently defeats the purpose of running NS on the
mailserver

Thoughts? ideas?opinions?

TIA