[whpalmer4]

What I was trying to ascertain is if that list is likely to be static over the course of a day, or if you'd have to recompute it over and over again. I don't know how big your database is; with mine, the script I cobbled together as a test takes a few minutes to run, and would be acceptable if I only had to run it once, but not so great if I needed it updated hourly. if you always use the same start time, it wouldn't be such a big deal, but if you have things coming to life all throughout the day, you would need to recompute more often, or use a different perspective (context grouped by start date, probably) to check for such things in between runs.