ISM Web Server in DMZ

Hello All

I have a Question

i have 2 web servers and 2 app server and a backened DB in my local network and 1 webservers in my DMZ

i use heat.app.com to access the internal solution and use heat1.app.com to access the application via the DMZ and external users as well

I hav been able to remove the application tab from the internal url heat.app.com using the alternate login on configdb tenant

The login page heat1.app.com on the webserver on the DMZ keeps prompting me to select either ConfigDB or Gold which is the second tenant. How can i remove or default the login page to Gold  .