Disabling GTM Persistence selectively

OK, I'll give myself a big fat RTFM:

ttl Overrides the default time-to-live value. Overrides the default time-to-live value. If this command is used for a CNAME, the value overrides the default of 0. If this command is used for a pool, the value overrides the time-to-live value for that pool.

when DNS_REQUEST {
  if { [IP::addr [IP::client_addr]/24 equals "10.1.1.0"] \
    or [IP::addr [IP::client_addr]/24 equals "10.2.1.0"] } {
      ttl 0
  }
}

At the wideIP level, I presume this means persistence, and at the pool level, I presume this means the actual TTL. How do I ensure this is applied at the wideIP level?

....unsolicitated commentary to follow...

Could something other than TTL have been selected as a nomenclature for persistence on the GTM?