Here at COYO, we can understand your concerns. You want to ensure that documents are only shared internally within a set group of people. As the requirements here differ from company to company, we don’t offer any out-of-the-box solutions, such as integrating a notice. However, you can find two options here for how you can handle this during your daily work:
Restricting the group of people
Creating, managing and deleting document links is controlled via the permission "Manage and create public links for files in documents".
If you don’t want links to be shared and you want to proceed editorially, only assign the permission to a certain group of people or deactivate the links if they are no longer required.