Hi Helge ,
I've found a partial solution - I think! Try setting up your recurring
tasks and then expand them by clicking the + sign. Now highlight the
individual tasks and outdent them. Now delete the original recurring task.
This should leave you with just the set of tasks. Now here's the funny bit,
select all the tasks but the top one, indent them, and in Project/Task
Information/General tab, set them to roll up to summary. That seems to
work, but you'll have to re-insert the first meeting as a separate task.
Why it works like this, I've no idea!
Hope this helps - please let us know how you get on
Mike Glen
MS Project MVP