How to make private frameworks ?

I have some frameworks used by my app, but I don't want that the end-user install them in its Library/Framework folder…

To achieve this, you need to have access to the source and project files. Open the project in PB and set the install path to
@executable/../Frameworks, and build it.
In the project using the framework, add a Copy phase that will copy the framework into the Frameworks folder inside the application bundle.