Event timestamp and duration can be obtained in the Rule’s then part:
// declare the accessor interface, it will be automatically injected
global co.streamx.kie.api.runtime.Events events;
rule "GroupCreate"
when
// for every new EventA
$a: EventA(!seen, $time: eventTime) from entry-point events
// check there is no group
not (exists(Group(eventTime == $time)))
then
// getTimestamp method accepts event instance and entry point name
long timestamp = events.getTimestamp($a, "events"));
// getDuration method accepts event instance and entry point name
long duration= events.getDuration($a, "events"));
end