Time-slicing option for trigger functions

I would like to have an ability to fire a trigger with a time-slice condition. For example, I would like to say: fire a trigger if the current utilization exceed average utiization of the link for the last 7 days during working hours.

I realize that it may be possible to accomplish something like that with passive checks and flexibile scheduling, but that would make the configuration a lot more complicated and eliminates the use of active checks.