You can also show relationships between multiple projects by linking tasks across projects. To create an inter-project dependency, you first need the project's System ID  of the predecessor task. This can be found on the Project Details view of that project.

 

• Go to your project on which you need to create a dependency.
• Select the Interactive Gantt view from the View drop down, if its not already selected.
• Select the Columns button from the toolbar and add the Predecessor column to the grid, if not already added to the grid view.
• Select the task for which you need to add a predecessor.
• Type the ID of the predecessor task prefixed with the System ID of the predecessor's project in its Predecessor cell. So, the dependency you set in the predecessor column will look like 147497:34. The default dependency type is finish-to-start (FS). You can also indicate alternate dependencies (e.g. FF or SS) to model your project realistically. E.g. 147497:34FF

To view dependencies between projects: 

1. Create a report of type 'Task' with output type as 'Gantt'. For steps, refer here.
2. The Gantt part will show you the dependencies as seen in the below screenshot.