Idea Summary
Currently, when you create a new list entry, you can set the target type as ‘page in this application’ or ‘url’. Is it possible to add the option ‘page in other application’? 

Use Case
We're developing an application that consists of multiple apex apps. We want one common navigation list in the whole application, that links to pages in the separate mini applications.

Preferred Solution (Optional)
Add a new entry to the select list ‘target type’: Page in other application. Then you can enter a application id and an page id.