I'm looking for a CMS that can do the following:

I wish to create a site that is for music fans.  But it gets a little more complex.  For example - each singer has their own unique website and layout.  Their content however, can be searchable from other singers websites.  But at the same time, the content does not have to be shared.  ie there is an option to level of sharing function.  And there is a different administrator for each singer and they can dictate which content on their site will be displayed and what is available to other singers.

Preferably a free or relatively cheap product
uses an oracle database.
Allows multiple templates to be created for sites.
The "look and feel" of each sites is customizable.
Multiple groups that can share content among themselves.
The product should be platform independent.

Thanks in advance!

I think drupal would be nice, but I don't believe they support oracle databases.