Problems having 2 dbt projects and assigning one model from one project as a source for the other project

The problem I’m having

We have 2 dbt projects. Project A is our main dbt project which is scheduled to run 2 times a day. Project B is another project which has 2 models that are needed to run every hour. The 2 models in project B get one of our models in Project A as a reference. In order to not run that main model in Project B, we tried to put that model as a source for Project B. However, we noticed that in the Project A run , this model( that we put as a source in Project B) was skipped. Therefore this model didnt get updated and the following models in Project B also didnt get the updated data.
In our project B yaml file we tried to show that this model is a source but in our logs we got an error that the source is undefined.

  - name: XXX
    schema: "{{ source('XXX', 'Model_name') }}"

Is there a way to use that model in Project A as a source in Project B?
Thank you !