I followed the step given in below link to configure multiple content stores in Alfresco 5.0.d.
http://docs.alfresco.com/5.0/concepts/store-config-fullexample.html
Alfresco instance is not able to start and gives the exeption,
Cannot resolve reference to bean 'storeSelectorContentStore' while setting bean property 'store';
nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'storeSelectorContentStore' defined in file [/opt/alfresco-5.0.d/tomcat/shared/classes/alfresco/extension/content-store-selector-context.xml]:
I also tried the method stated in below link, https://community.alfresco.com/docs/DOC-5156-content-store-configuration
This gives a different error, alfresco dir root not defined even though it's defined in the properties file.
Marcus is right about this being an Enterprise only feature, but you could develop your own. It shouldn't be too much of a hassle.
Also, have you tried using this extension, I suspect it has everything you need and is maintained by a well know Alfresco contributor?