Multiple SSO config

Hi All,

we have configured an SSO setup(on Dev Portal) for our dev/qa enviorments and would like to setup another SSO(on PRD portal) for all the production instances, and have the below queries 

1. When we import the registry entries for SSO enrollment will it overwrite the existing URL or can we have multiple URL enrollments 1 for dev/QA and 1 for PRD .

2. Would we also have to import multiple root CA into the users browsers .

regards

Jonu Joy