Elgg does not have a elaborate roles and permissions system built into core. Although in theory this could be built using a plugin, I think that computing the access control features you describe could be very time consuming and really slow down your site. I recommend sticking with the access features that Elgg provides.

Thanks for your response Kevin. 

So, basically, there is not an easy way to add another access option to the default elgg access features. But it makes sense to have some way to add additional read access options to profile metadata without forking core code. I do not know how to do it.

Thanks anyway.