Hi, I need your HELP!!!

I have similar input - please note, I have lots of PROSPECT nbrs with adequate events/meanings/durations - only for simplification, I inserted table with only 2 unique PROSPECT nbrs.

My question is - do you have any idea, how to sum up EVENT DURATIONS for PROSPECT nbrs and for EVENTs?
I mean, f.e I want to sum up event duration for PROSPECT 123456 - from EVENT 1 Start till EVENT 27 270 Confirmation (00:03 + 10:01 + 0:08 + 125:47). of course, i need same calculation for the other PROSPECT nbr 555555 - from EVENT 1 till EVENT 27 (00:04 + 12:57 + 00:22)

Any ideas how to solve my problem??
thanks in advance!!!!

PROSPECT EVENT MEANING EVENT DURATION
123456 1 Start 00:03
123456 62 Submission 10:01
123456 27 Confirmation 0:08
123456 27 270 Confirmation - other 125:47
123456 80 Change 00:15
123456 80 Change 00:04
555555 1 Start 00:04
555555 62 Submission 12:57
555555 27 Confirmation 00:22