Aggregating a Table

I have a list of sequential 'Activities' in a table, a 'start time' and 'endtime' describes when these happened.

I wish to have a summarised table that will GROUP each activitity type. For example, in the picture below, all the entries for 'Production' and 'Delay' will be grouped as per the right hand table.

Any advise would be appreciated!

BI 4.1 SP5