Hi Dorga
As far as I understood....
There's a possibility to backup other master/media servers catalog db, its volume and media db's.
For DR on FS base it depends if you use UX or MSWindows, some stuff can't be covered through backups on the Unix side, but there's another VxNBU extension called BareMetall Restore.
Was this your question ?:
Furtheron, to merge a catalog DB is one thing, but to merge different media and volume DB's to one single DB, that's impossible (at least without knowing the exact structure of those mentioned files or the right tools - if existing).
About 2 years ago (VxNBU 4.5GA) I did ask VxSwitzerland as a contractor about for an international and big customer, but there wasn't any chance.
How we solved it:
We have 2 Solaris Server clustered (Vx) as one single master server. The DB stuff lays on EMC disks, the application and OS on local disks. If one or, more worse, both master server would fail on OS base, we would jumpstart the OS, reinstall the basic VxNBU application and recover its configuration and DB information from the DB tape, and finally we would restore the whole system (excluding files/folder from the previous restore).
Cheers
Flave