Can you please give me a little bit more information on what you would like to do? It is possible to view all sessions with 'isi smb sessions list'. It is also possible to view all open files with 'isi smb openfiles list'.
Just remember that the isi smb sessions list and isi smb openfiles list commands only show information for the node they are executed on. If you want to look at the whole cluster you would want to prefix that with isi_for_array -s
What I am trying to achieve here is to obtain a similar out to showmount -a <node ip address> which can be used to list all nfs shares and host mounting it.