You can point it to a different instance of the same DB server but that is about all. HOWEVER, and this must be read very carefully... IF the two Domain Managers can be built on completely segregated networks with ONLY the DB Server available to both networks but accessed via different NICs; built on identical images, with identical names and HostUUIDs and both were NEVER on at the same time...then you likely could do this as it would essentially be an automated MDB move procedure or DM rebuild, but it would have to be VERY CAREFULLY maintained and could very easily result in problems.
That said, there is virtually no real reason or benefit to doing this as it is not a valid DR configuration. If you lose the MDB server you have 0 DMs.
The proper way to do it would be to have two 100% segregated networks, two SQL servers and two DMs built identically. Then you drop the MDB on the DR side, do a daily FULL BACKUP of the production MDB and move a copy to the DR SQL server every day which could be then used by the DM copy should the primary DM and/or DB server be lost. You can then take the Production DM and DB server offline, update DNS and put the DR DM and DB server on your production network to resume activities.
Thanks,
Joe Puccio
Senior Engineer, Software Support