CCK, Node Reference, and Relational DB Problem

We are using CCK to build a custom content type. Each content type has some body-content, a title of course, and then needs access to a Parent ID, a Child ID, and a Grandchild ID, which are important for building pages. IMPORTANT: Some pages might share these IDs. They're not necessarily unique for every page. There are 10,000 content pages, and only 100 mixtures of these IDs, for example.

In the interest of database structure, we wanted to avoid redundant data. So rather than every content type having three individual values, we want ONE reference value that refers to another table.

In our current database (on a custom CMS we are replacing with drupal), a content page might have a category ID of 1. And that value of 1 corresponds to a category table, and the row with CatID 1 might have (parent ID, child ID, and grandchild ID) values of (4, 58, 2).

I couldn't see how to set up this relationship with CCK. Then I thought about using a node reference. I created a new content type called Category ID and gave it fields of Parent, Child, Grandchild IDs. Then I went to my original content type and added a node reference to this new CatID content type. Eureka! Now I have parent, child, grandchild in a seperate table (good) and a hook between the content types.

Except there's a problem. By creating another content type to store this category info, I'm essentially creating more nodes. Suddenly, I'm not referencing a category ID, but a node ID -- and those node IDs are being created by drupal. Since we've already loaded up some data into Drupal... I can't have a "category ID" (or node ID) of "1"... Instead, it's 291. Node 291 => Cat ID 1, Parent/Child/Grandchild of, say, 4, 58, and 2.

And suddenly, this node reference thing won't work... Because instead of Category ID of 1 = 4, 58, 2... I'm forced into Category ID of 291 -- which maps to completely different values.

Bare in mind we are importing our old CMS content... So I cannot change each page's category ID. It's expecting that 1 = 4, 58, 2... and not, in this example, 291 = 4, 58, and 2.

Node reference is close to what I need... But as you can see, it's creating some problems. Am I going about this wrong? Is there a more elegant solution? Do I need to contract a drupal developer to create something new?

Please let me know if you require additional information. We're dropping our entire CMS for Drupal. We've become believers.