how do u compare timestamps on different rows that are related to same event

Oracle 9i on Sun Unix on Sun Star server

a batch process runs every 6 hours. its composes of 10 stored procedures that run one after another assuming prior one finished ok. each procedure logs when it started and when it ended. total takes 20-30 minutes but sometimes 1-2 hours.

we have following table

event name                      date

web login start                 7/1/04 9:24:14
web update start                      7/1/04 9:24:36
web update end                      7/1/04 9:28:40
web insert start                       7/1/04 10:34:15
web insert end                      7/1/04 10:45:14
web login end                       7/1/04 10:49:22

web login start                 7/1/04 15:24:14
web update start                      7/1/04 15:25:36 ....

what we want to see is following

event start event end total time

web login start         web login end       1:25:08
webupdate start        web update end    0:4:23  etc

and 2nd batch 6 hours later

web login start         web login end       1:25:08
webupdate start        web update end    0:4:23  etc

we want the ones related to each other in each batch

is this possible?       Received on Tue Jun 08 2004 - 19:56:14 CDT