We are developing a library (MyLib) which includes two modules, say Module_1 and Module_2.
The folder structure is as follows.

            MyLib
              |
        ---------------
        |              |    
       Module_1    Module_2  

There is a manager who is responsible for the release and version control of MyLib. Two independent teams are developing the two modules. Module_1 depends on Module_2 and vice versa.

We would like to maintain independent version controls for MyLib, Module_1, and Module_2.
We can maintain a git repo on MyLib so that the Manager can have version control on MyLib. An ideal configuration we can think of is as follows.

                 MyLib 
                   |
    ----------------------------
    |              |           | 
   Module_1    Module_2      .git
    |              |
   .git           .git  

Now, how to configure the independent git modules for Module_1 and Module_2 so that each team can independently go back to any previous versions?
For example, the team developing Module_1 will be using a particular version of Module_2 and they should be able to go back to this particular version of Module_1 and Module_2 from its git repo at any future date.

I found that including a Folder outside the git repo is not straight forward.
For me, our situation is a common scenario for any library which has multiple modules developed by independent teams and have dependency on each other modules.
Can somebody throw light on handling this type of scenario?

I checked git submodules. But I don’t think it is the right choice for our use case.