[rules-users] drools fusion: rule of type 2 minutes before event A finishes

Hello, I have following use case in drools fusion: event A has specified duration (different for each occurence) I would like to fire rule if event B does not happen eventA.endTimestamp -2minutes. e.g. event A has duration 20minutes, it's inserted on 13:22:00, then rule should fire on 13:40 if event B does not occur before. I looked on temporal operators - but could not find anything suitable, it should be sth like: when $eventA not (EventB( this after[ negative infinity, -2m ] $eventA ) then ... end - but there's no infinity symbol in drools, nor java ;) Any ideas? thanks & br, maciek