This example shows how to split big projects into smaller sub projects
but still have cross dependencies. This idea is to export certain
tasks as fixed tasks from one project (project1) and include them in
the other project (project2). So project2 can reference tasks from
project1 without knowing all the details and without the need to
combine both project into one mega project.

Project1 and Project2 share a common resource pool. The resource
allocations can be included in the exported files, but the project
part that is scheduled first, always gets it's resources first. The
including project then has to live with the remaining free slots. With
good project and resource partitioning this should be no problem. If
you can't take that route, you have to take the mega project approach.