Overriding TTL per resource-record on slave

[blrmaani]

We slave a zone and would like to override default TTL for bunch of resource-records. What is the right way to do it?

For example, here are few records for which we have to customize TTLs:

host1.zone1.com.:
  default_ttl = 300 
  preferred_ttl = 3600

host2.zone1.com: 
  default_ttl = 300
  preferred_ttl = 86400

Since we want these preferred TTL values only for few regions, we don't want to make changes on our hidden master and prefer to do it on the slave sitting in a specific region.

My Idea is to run a dynamic update (nsupdate) wrapper script to update TTL entries for desired resource-records on our slave. Is there a better way to achieve this?

thanks
Blr