Yes. I understand that I might have one call that goes on for 2 days and overlaps with 1000 different 1 minute long calls... and that still might not satisfy my criteria of 24 concurrent calls - if the 1000 calls are all consecutive instead of concurrent.
However, my point is that when I DO have a situation where I have 24 concurrent calls then EVERY single one of those calls overlap with at least 23 other calls. There is never a situation where I would care about a call that overlaps with less. So by filtering out (or in rather) all calls that overlap with at least 23 others (which is what we did previously) I can start to narrow down my list of calls.
Now I'm sitting at 4k calls (instead of 30k) and I can start to figure out which ones in that 4k happened at the same time.