SLD and XI question

Hi All,

Our XI server is registered in a different SLD server than the Portal server. Our requirement is to integrate the external web service with portal using XI, so in this scenario

1. Does the portal and XI needs to be on the same SLD or they can be in different SLD servers for the portal and XI integration ?

2. Can we create a new technical and business sytems for portal in SLD where XI is already registered and do the integration with XI ?

Thanks

Steve