Release : 21.2
Component : IM Reporting / Admin / Configuration
At this time Performance Management only provides aggregate Event thresholds against CPU or Memory component items.
Thresholds are only on a per item basis right now.
CPU/Memory utilization is the exception allowing you to do aggregation to device level of all CPU or memory components polled in 1 poll cycle.
Interface Event aggregation at the device level for all interfaces, or for sub-interfaces aggregated to their parent interface, would require an Enhancement Request.
There is a feature to add some aggregated threshold ability across devices, but no date specified on when it's planned to be released.