Block connection (so many sessions)

Hi,
I’m using Peplink 580 with firmware 6.3.4s008 build 3628
May I stop the connections (IPs) that create so many session
It make the peplink is overload
I found this topic but still have no answer.
Client Session Limit Feature
But is this feature available now ? or are there any way to do this ?
thanks and best regard !