Re: Pivot Table Gantt Chart with multiple start and end dates
I have no idea if it's possible with multiple dates. You could try to synchronize your dates with a canonical calendar: Canonical Date. Another approach would be a change within the datamodel and including all start-dates into one field (with end-dates the same) and using a further field to differentiate between them which is than used as another dimension within the pivot and/or as a (set analysis) condition within the expression.
If you don't know them the following postings may contain some further ideas for your task: