No, 2 Mendix apps cannot share the same database. If you want to create the architecture you describe, create 2 apps and build integrations between the apps to support your requirements.
Hope that helps,
What if it is the same application deployed to 2 differents clusters but connected to the same db?
One application on cluster A will give access to only the Front UI pages and the other application on the cluster B will run the Back office. But both are working on the same db.
We will manage the navigation regarding to the value of an environnement constant.
What do you think?