We have 2 Tivoli Servers connected to our 3584 library w/ 8 SCSI drives.
Each server has its own connection to seperated tape drive loops.  We
had to do a Advanced configuration to specify drives and I/O slots.  Our
setup consists of 2 completely seperate TSM servers with their own set
of domains.  Is your setup a single server?  If so, the only way I can
think of making sure that your SAN Clients go directly to the fibre
drives is to create seperate device class and create their own primary
and secondary tapepools for the fibre drives.  Then create a management
class that sends data to the pools that are associated with the fibre
drives.  After that you just need to make sure your data is associated
with the correct management class in your opt or sys file.

Hopefully that helps,

Bud Brown
Information Services
Systems Administrator
Denver Health & Hospitals