Complex blackout dates for tasks

It would be great if we could use a cron to describe blackout dates, rather than specifying static dates. For example, I would like to set a schedule that runs hourly, with the exception of the 1st Sunday of every month. As of right now, I might have to accomplish this by creating two Tasks, one for every day except Sunday, and another for Sundays 2 thru 5 each month. It would be better if I could just have one Task, with a basic (non-cron) 60-minute interval, and a blackout cron that specifies the 1st Sunday of the month.