HOW to set up NOT authorized for new customers?

I figured it out ... took a whole pile of modifications but I was able to achieve the majority of it with one handy little "if" statement:

if ($_SESSION['customers_authorization'] == '0' and $_SESSION['customer_id'] != '')

If anyone else is ever looking for assistance on making a similar modification and you come across this thread, I can certainly walk you through the process as I was sure to add comment tags to all my edits to re-locate them in future.

@CapitalC can you describe what have you done?
I need:

1. Guests to show only the prices of specific categories, as described in this post: http://www.zen-cart.com/forum/showthread.php?t=164960
   and I managed to do that.
2. I want for the specified categories customers (logged in) to be able to see the prices, but not for the others.
3. Only some customers to se the prices and add to card from ALL the categories.

So, you're saying it is possible to require registration to access the cart, and during approval, I can select that customer's access level?
I"d love to have a "browse without prices or check-out" category!

But more importantly, I need to sort my customer list by level of access so I can customize emails accordingly. Has anyone mastered that?