NFS Cluster questions

1. are there recommanded stonith that I should use for different setup? for example, I am setting up NFS cluster, I am using fence_scsi. Other then better ones or different ones I should be using?
2. after I created first group NFS resources, I assigned a name to it pertaining to its purpose. now I am creating the second group and need to use the same float address. It's not giving me errors, but only the latter shares are showing up in showmount command. how do I go about accomplish this?

I am new to RH and its cluster, thanks for your help.