I suggest taking a look at the "Network Activity" view, I think it contains relevant information for you.
I think you should be able to see concurrent connections in SmartView Monitor, activate "Monitoring" blade on the GW and take a look.
A few thing about SmartView and the new views/reports:
1) All the information is derived from the logs. So the thumb rule is as long it's in the logs and the logs/field are indexed by the SmartEvent.
2) SmartEvent doesn't index connection logs so if you have relevant info I would advise to go to the relevant rule and mark in track options "Session".
3) In SmartView (SmartEvent app that is in charge of views/reports) is that it's very intuitive to create your own "widgets" which performs a query on the logs and bring the desired information. I attached a small file you can use.
Kind regards, Amir Senn