Is there a way to automatically mark a page (with colour) that certain users have access to?

[lharman]

Other companies have access to certain pages and spaces within our confluence. Yes we can review the permissions and restrictions and mark each individual page with macros and a colour, but is there a way to set up some kind of filter that automatically marks a page when 'external' eyes have access?

Maybe through a keyword? e.g. the company name from the email address? 

Any help is much appreciated!