There are several ways. One way in rules is to use the trigger “SharePoint group membership”. You then use the group number which is found in the address bar when viewing the group. I would probably use “if not in a group” and then in the hidden tabs section use the tab unique ID.
Another way is in the tab itself. There’s a section called “Which groups can see this tab?”. There you can specify which groups have access.
I sometimes create Permission Groups on a site for the sole purpose of managing visibility of tabs in a DFFS form, when the use case calls for it. You might already have groups that fit your needs. Since the “Which groups can see this tab” is a dropdown that shows you all the permission groups (by name) within your site collection, it is much easier to use than using a group in a rule trigger.