How can I hide portal interface (/suite/apps) from a group of users while anothe

Instead of hiding the portal itself for a particular group which you can't, adjust the security of your applications accordingly.

You can add the user groups who must access the portal interface/record as an administrator thereby giving them admin properties. The rest you need not add this will solve your problem.

In both groups the users are basic users. I want to let group A access /suite/apps interface and block group B from viewing /suite/apps interface, entirely. An administrator has all access privileges.

Abishekk, making end users administrators just to grant them access to Portal is not a good security recommendation.

There is no way to restrict access to /apps. Even if you disable the app dropdown, users still have access to /apps. You have not provided more details to your use case but per Eduardo, adjust access to your apps and to individual objects.

jasonr411 thanks for the suggestion, but we need not give admin access but we can give viewer access as the doubt was a particular group should access it. I guess end users will be given viewer access.