Think that this might be a charting issue...

On one sheet i have created input fields for a user to fill in.
The user can fill in data for four different projects.
Each project has a start and end date (yyyy-mm) where the dates can overlap the other projects.
I've created dynamic charts for each of the projects, but now I need a "total" chart for all the four. This is usually pretty easy if the start date of project 2 is after end date of project 1 etc...

But as an example:
Project 1:
Start 2007-01
End 2007-12

Project 2:
Start 2007-06
End 2008-01

The months is in row E13 and forward for project 1
jan-07 feb-07 mar-07 ...

The months is in row E44 and forward for project 2
jun-07 jul-07 aug-07 ...

When i'm trying to create one line graph of the two projects the months really screws up.
Anyone have any ideas?