setting IP address(es) and gateways on IBMi LPAR at IPL time based on server serial number?

We are using SAN based replication for our IBMi installation. The
production LPAR is completely replicated to the DR LPAR using Metro Mirror.
The DR LPAR is normally offline since it cannot be active while the SAN is
being replicated.

The issue is, when we shutdown production and then IPL the DR LPAR from
the SAN it has the IP configuration of the production LPAR but both
machines are in completely different subnets, with different IP addresses.
So that is not going to work.

While we can get onto the console from the HMC to fix the IP addresses, we
would really like to have this done automatically.

It was mentioned that the production LPAR could have two IP stacks created,
one for the production site and one for the DR site. Then on IPL the
startup script could interrogate the serial number of the server it was
running on and implement the appropriate IP stack. That sounds like the
right answer but we don't have the expertise or knowledge to know how to do
that.

Any pointers to some IBMi docs would be appreciated.

Thanks