Did this 20 years ago by having the name of the server as part of the user's profile.
User's 1 through 50 (light users) log in and their profile says they go to app-1.myapp.com.
User's 51 through 60 (heavy users) log in and their profile says they go to app-2.myapp.com.
A specific user may pay extra to have a non-shared environment, and this supports that as well.
User's 1 through 50 (light users) log in and their profile says they go to app-1.myapp.com. User's 51 through 60 (heavy users) log in and their profile says they go to app-2.myapp.com.
A specific user may pay extra to have a non-shared environment, and this supports that as well.