Eclipse allows to define 'Working Sets'. A working set may include a smaller number of projects that belong together. If selected only the projects that belong to a working set are displayed in the project explorer.
Creation/editing of a Working Set
In the Project Explorer click on the small arrow pointing down. Select 'Select Working Set...' from the menu. A dialog window opens. Here it is possible to define new working sets or edit/select/remove existing ones. For each working set the relevant projects may be selected from the workspace.
Selection of a Working Set
To open a working set open the working set selection dialog.
If a working set is selected from the user-defined list of working sets only the projects included in this working set will be displayed in the Project Explorer.
As soon as a working set was selected for the first time it appears directly in the selection context menu: