Dual Membership

I am setting up a website that will have dual membership that goes something like this...

I have a "Registry" membership that is a one-time payment "Lifetime Plan" (in a category called Registry) that will have a few custom form fields only for that membership.
Custom fields will be a dropdown list, and text entry - basically a list of phone number "area codes" (the drop-down list) and a "handle" (text field)

I will also have paid recurring Monthly (with 14 day Trial) and Yearly membership plans in a category called Subscriptions that I also want to share the info from the custom form fields available to the Registry plan. I am testing out a couple of different scenarios, but essentially they are independent of each other, but the recurring membership plans require an active Registry plan to show the "extra" custom fields on member profile/details.

What I would like to know/be able to do, is if a member only signs up for a paid recurring plan they won't have access to those custom Area Code and Handle fields... but if they have a Registry membership, then those fields would be visible/editable under that member's details/profile.

So, if a user has signed up for the Registry plan and entered his Area Code and Handle fields, they are added to his Joomla profile, then when that same user signs up for a paid recurring plan, his  Area Code and Handle fields don't show up on his recurring plan profile.

I would also like to know if there is any way to set custom fields to be unique entries? I don't want users to be able to register the same custom field "handle" variable in each "Area Code" For example, there could be 613 My Handle and 819 My Handle, but if somebody already has 613 My Handle, nobody else could use that combination.

Thanks in advance,

Jeff

Update...

Last item workaround: Using PHPMyAdmin, I created a new unique index on #__osmembership_subscribers table called idx_cb_call_handle from (area_code_cb_call and cb_call_handle) 2 of my custom fields... area_code_cb_call is a 3 character text field, and cb_call_handle is the user's CB Handle - the unique index works to prevent users from having the same CB Handle in the same area code, but allows users to have the same CB Handle if a different area code was entered (which is the way I want it) - the problem is it doesn't do the same field validation as username, and just throws a generic MySQL Error: Duplicate entry '613-Sample Handle' for key 'idx_cb_call_handle' which works in preventing duplicate entries, but not very "user friendly"