We don't track who is currently logged in right now.
If you enable WMI data collection, we should however track when the last login occurred and the last account to log in.
We leverage this in an out of the box search to help identify VMs where nobody has logged in for more than 30 days.
vm.env.os.lastLoginUser:* AND vm.env.os.lastLoginDate:[* TO now-30days]
Jon