Dear Sir,
The way I would do it is to take the default reference design and instantiate FMC30RF star twice, "AS-IS". Then I would modify the cid_package.vhd file to map other addresses to this new instance (this file is created by StellarIP and has BAR addresses of all the stars). You would do is modify the UCF to map the second instance to physical pin. Modify the data routers so they can have more wormhole and connect the new instance to the modified data routers.
The only thing I don't see in your post is modification of cid_package.vhd (in sip_cid). This dictates where the star are mapped in a constellation point of view.
Best Regards,
Arnaud