XF 1.4 Limit Non Registered Users Seeing User Profiles (Member List)

I am hoping this is something that someone has a ready answer for ...

I want to disable ability of visitors / non-registered users from seeing the list of members. I have set so that the member's details are not visible to visitors, but a visitor can still see the list of members.

One of two ways ... disable the toolbar menu option until the user signs in or if a visitor signs in and clicks "Members", the list will be blank with a message stating that they do not have authorization to view. I would prefer disabling the menu option itself.

Anyone help? Appreciate it.