How to create "parallel" tasks?

[A.S.]

Hello together,



have the following problem:

I have a Project plan that contains a base development section and several customer activity sections.

In the customer activity sections, I want to show a task that summarizes several base development tasks. Therefore, I want to start the summarizing task at "base development Milestone #1" and it should end with "base development Milestone #2". The Goal is that the summarizing task should change its duration automatically with the start/end Milestones accordingly.

I want to make an example, for better understanding: let's assume I want to develop a total new screw, let's call it the "67/18" screw". The Project starts with Milestone #1 and I have to do several things: find out the right material for that screw, prepare CAD models and drawings, let the sample shop produce some of those screws, make screwing Trials etc. ... finally, the Project Ends with Milestone #2.

In my customer section, I don't want to Show all that in Detail, I only want to Show one task, named "development of 67/18" screw", beginning with Milestone #1 and ending with Milestone #2. The Duration should Change automatically if the Milestone are shifted.

I tried to link the summary task with both Milestones, but it does not work without defining a Duration for that task. Does anybody have an idea?

FYI: I don't have ressources allocated to my Tasks.

Thank you and best regards,
Alex