Just to mark this question answered, I'll summarize answers and when they are appropriate.  1. If you anticipate that only a small percentage of hosts will need storage with multiple policies and if you do not anticipate the need to move a single lun from one policy to another, the simplest thing to do is just associate a FAST policy with the SG in the masking view. When storage from a 2nd policy is needed, just create another SG and MV with appropriate policy associated.  2. If you frequently need multiple FAST policies for the same host but never anticipate moving a single lun from policy to policy, then cascaded SGs are probably the best bet.  3. If you anticipate needing multiple FAST policies for the same host frequently, and if you also expect to have to move individual luns from policy to policy, then see SANMAN386 comment above and reference the seconf option in that comment. 
Question about managing FAST on a VMAX. We're being told by EMC to create duplicate storage groups for groups to which we assign a FAST policy. One group goes in a masking view and the other just gets the FAST policy assignment. The issue I have with this is that if our storage administrators add storage for the host, they have to remember to also add it to the FAST storage group. We also end up with twice as many storage groups as we would otherwise need. Seems like an ugly solution to me. If you're using FAST on a VMAX, how do you manage the policies and storage groups?  Thanks, Vic
FAST_VP Storage Group Admin