How to configure multiple repositories active on an Oracle BI Server machine?

Analytics server does support multiple RPDs per Server instance. You will
need to add them to the {Repository] Section in NQSCONFIG.INI as a separate
line item, and with a different name than 'Star'. 'Star' is a logical name
for the RPD, which is referenced by the ODBC drive that you set up for the
Presentation Server or whatever other front end you are using. For example:

Star = demo1.rpd, DEFAULT;
Star2 = other.rpd;

Then, depending on which RPD you want to use, you point the ODBC driver to
that particular logical RPD name (star or star2). If not is configured, it
will use the one that is default