A question I’ve been asked a number of times recently is can OBIEE 12c have multiple instances running from a single installation (aka multi-tenancy).
The short answer is no. The first releases of OBIEE 12c do not support multiple instances, only a single instance is permitted.
the following two documents on metalink confirm this:
However you can have multiple installations of OBIEE running on the same server, but they need to be completely separate installations with their own configurations – different Oracle Homes, different port numbers and separate RPD/Catalog/Security and different scripts to start/stop/manage them.