Python combine multiple projects to one global project

Question

I was wondering how I can combine multiple projects, each of them within an own virtual environment, to one global project.

For example this structure:

Python
|
|-- Send_Mails
|   |-venv
|   |-main.py
|
|-- Create_Files
|   |-venv
|   |-main.py
|
|-- Scrape_Web
|   |-venv
|   |-main.py

Each project has it own purpose, but from time to time I need a Send_Mails function within Create_Files. I wasn't able to simply import the send mail function from Send_Mails inside of Create_Files due to a ModuleNotFoundError.

What is the trick to do this?