I think you could generate a table with intervals you'd like to achieve (perhaps autogenerate them based on your start time) and then join these intervals onto original table using IntervalMatch
Hope this helps.
lets assume there's a table called Table1 with a field called Timestamp which contains your timestamp. Then you can:
Min_Timestamp: LOAD Min(Timestamp) as MinTime, Max(Timestamp) as MaxTime resident Table1; Intervals: LOAD FieldValue('MinTime', 1)+((1/24/60)*3*(IterNo()-1) as StartTime, FieldValue('MinTime', 1)+((1/24/60)*3*(IterNo())-(1/24/60/60) as EndTime Autogenerate 1 While (FieldValue('MinTime', 1)+((1/24/60)*3*(IterNo()))<FieldValue('MaxTime', 1);
So if your first time is 17:00:00, then your intevals would be
17:00:00 - 17:02:59
17:03:00 - 17:05:59
And than you can proceed with the intervalmatch.
I'm pretty sure there are typos in my script, I did not test it, so you will need to fine tune it.