question about caching & bind

Hi,

I currently run a split DNS scenario and was wondering about caching
to possibly improve performance. Is it possible or even advisable to
have 1 or more DNS servers (say internally for arguments sake) utilize
another separate bind caching only server ? My thinking is that if one
or both of the servers is rebooted I lose the rich cache it has
created and it would be nice to prime the lost cache quicker. If so
what is considered best practice ?

thanks,
Joel