Product only available when logged in

I have the most recent version of zen cart.

My client would like to offer a service that is only available once the customer pays for one service and the other service is ONLY accessible when they have paid for the first service. It's not a buy one, get one free, but a free service that may either appear in the customers account once they log in or maybe a link that is available, that appears somewhere, once the customer signs up and pays for the first service.

I hope I didn't make that too wordy.

Here is the web site:
http://www.healthsalesreps.com/healthsalesreps-cart/

I appreciate any help any one can offer!

Jim

Through a combination of some module for product display to only a certian group and a MANUAL adding of a new account that makes the required initial purchase to a group one can get close....
With much additional custom code one could make the assignment to a group after the initial purchase programatic but this cost to code might not make this as desired once known as it is before knowing the cost

So the free service is CONDITIONAL to the customer having purchased (at some point), the primary service?

Am I right in thinking then, that the system will therefore need to do the following:

1. If the customer is NEW, and adds the FIRST service to their cart, then the SECOND service must be made available to them so they can add it to their cart at that point as well.

2. If the customer is EXISTING, and purchased the FIRST service earlier (perhaps a week ago), then the SECOND service is made available to them, WITHOUT them having to also add the FIRST service to their cart again.

I'll try to explain it easier...

If the customer purchases the first service/product, then the second service/product will become available to them after the first purchase but they would have to log in to their account to have access to that second service.

Any ideas?

So only point "2" in my post above applies...

Somehow a "conditional" will have to be inserted that checks the purchase history of a customer, and if the product has been bought, then the second product is made available...

... could be done I suppose, but will require a bit of custom coding. (and I'm not the person to ask for that!)