Following two commands are good enough to find out how many remote Hosts are connected to your storage via 'igroup'.
::> igroup show -fields initiator
::> vserver iscsi initiator show
This command gives real-time status of connection activity:
vserver iscsi connection show
vserver iscsi session show : Displays all session information for the specified Vserver(s). An iSCSI session can have one or multiple connections. Typically a session has at least one connection.
Powershell:
PS C:\WINDOWS\system32> Get-NcIscsiInitiator
PS C:\WINDOWS\system32> Get-NcIscsiSession
PS C:\WINDOWS\system32> Get-NcIscsiConnection