Hi Christina,
Another perspective is that maybe you are correct to have created 3 separate projects, but the tasks shouldn't exist in each project - only in one of them. HOWEVER, you may want to view all of the tasks together as a single virtual project. In this case, you could create a task report and filter it to include tasks from the 3 projects, therefore giving you the combined view.
Using the cross-project-predecessors in addition, could still be handy in the above scenario.
Regards, David.