Base the sub summary report layout on the interruption table.
You'll need 2 sub summary parts (leading) and a body part. Put sort by Project name in the highest sub summary part. Then put sort by Task name in the second sub summary part. Then put interruption name in the body.
Sort by project name, then task name, then however you want to sort by interruption name (alphabetical, date)
Nothing happens until you sort
I was about to post the same suggestion as Steve. Instead I will just observe that we are both assuming a certain set of relationships here:
Projects----<Tasks-----<Interruptions (----< means one to many )
thanks for your support
but can i show the tasks in the report without having interruptions on them
my managments would like to see all the tasks even without the interruptions.
Then you may need to base the layout on tasks and use a portal to list the interruptions.
that solves my problem