[Koha] Using Koha in consortium

Hi Can Koha be used in a consortium environment? Is there any special procedure in setting up the environment? I have just installed the Koha 3.0. It seems that it is a two-level structure: Group and Library. 'Group' is used to indicate a library . 'Library' is actually a branch in a library. In theory, we can set up different 'Groups' for different libary members. But we are using a shared catalog, therefore, we may need a three-level structure. Any advice. Regards Henry Manager Singapore Integrated Library Automation Services (SILAS) http://www.silas.org.sg