Creating Virtual Projects
Virtual projects are not real projects, they only exist to group different projects. You may create any number of virtual projects and add them to any level on project hierarchy. Different than real projects they are shown with a folder icon and you can't create issues for virtual projects.
To create a virtual project, just write the name of the virtual project and press the '+' inside the virtual projects section. This will create the virtual project and add it to virtual projects list. From this list you can drag & drop a virtual project to project hierarchy on the right hand side of the screen. You can nest virtual projects under other virtual projects or real JIRA projects to create subproject hierarchy.