How to build a project correctly?

Question

gulp.js

The general structure of projects:
AllProjects
- tools
- - lib
- - project1
- - project2
- - project3
- modules
- - module1
- - module2
lib - consists of several dozen js files that must be built in a certain order.
project1,2,3 - js and css are collected here. Since project1,2,3 require lib, it must be sewn into the inside of the project ...
In turn, one of the required project is sewn into modele1,2.
So in lib I created a tax that collects all js into one file.
When building a project, when js is being built, I must somehow call the lib task (do not specify the lib assembly in each project, which in turn will lead to module1,2,3)
What to use for such an assembly, or how to call dachshunds from tasks?

Answer 1

Why such difficulties? Here is a nice build

Answer 2

It's not in my power to choose the structure =(