How to find a projectitem in a project

I have a solution which has several projects in it.

I generate files with .tt templates and have to add them at the right place.

An image of the project setup:

When a user chooses to generate a factory in Business.Customer.Server\Adresses\Factories I also have to generate some files in Business.Customer\Adresses\Entities.

Is there a simple way to get the project item of Business.Customer\Adresses\Entities?

I now have it working with finding the Business.Customer and then going down into every child till I find the correct projectitem.

Anybody knows an easier way to get this done?