What i can suggest here is that you should opt for Acrobat DC subscription plan for all of your 8 users.
1. Install Acrobat DC on all Terminal servers you have with named users licensing (Steps at Common Deployment Options — Enterprise Administration Guide )
2. Block Acrobat usage via group policy for all other users except the users who will use it.
3. Now when these users will log in they have to sign in once in Acrobat and will be able to use Acrobat without having to sign in again next time.
You can refer the Acrobat ETK for more information on this.
Regards
Ravi