Hang on @Gigitsu I have you covered with my own contribution to Phoenix xD.
Check out the :reloadable_apps option that I added to Phoenix a while ago. My use case was similar but not identical, so I am wondering if it will work for you.
config :your_app, Backoffice.Endpoint,
reloadable_apps: [:frontend_1, :frontend_2, :backoffice, :core, :common]
