Oracle 8.1.6 on SCO Unixware 7.1.1

Hi Friends,

I am going to start uing RMAN for backup and recovery.
I will be creating a recovery catalogue in the same database as my OEM repository.

I need to know whether a recovery catalogue in a particular database can hold backup/recovery information for several other databases i.e. prod/ test/ dev.

How does RMAN distinguish between the several databases it is holding information on ?

Thanks

Suresh