One way to achieve this is by configuring different URL for different applications:
When you hit the URL, Pega creates an unauthenticated browser requestor with an unauthenticated access group specified in the BROWSER Requestor Type for that system name.
If you have different nodes for different applications, then you can create a different system name for each node and have custom screens for every system name. Login screen customization will be based on the system name. Pega loads the browser requestor based on system name and based on this requestor we get the login screen associated to the production ruleset mentioned in the access group associated with this requestor. Please find the below link for customising login screen.
Thanks Vikas, I checked this solution with Pega ,they said it is not valid. There will be lot of config issues if we change the System name as PDC,Kibana etc are configure to work based upon System names.