Hi
Yes you can setup 2 vfiler DR in different sites for the same source vfiler. You just have to make sure their replication schedule do not interfere with each other.
I presume you have you got a snapmirror fiber channel interface on all three controllers in all three sites. You need three Controllers.
Site 1 FAS1 Controller1 vfiler
Site 2 FAS2 Controller1 dr vfiler1
Site 3 FAS3 Controller1 dr vfiler2
Regards
Boris