Can I "fake" an object model on top of a flat ActiveRecord?

This might be a painfully bad idea, but it's gotten me curious. I have a generic object Node, which has a name attribute. Say for example that one of the names is "Widget".

What I'm wondering is, is there a way to manipulate ActiveRecord to make a class named Widget, that behaves exactly like a Node with the only difference being that all operations only work on the condition (name="Widget") is true? I can do a simple class Widget < Node to get it started, but I'm looking for what the next line would be, where I can specify the global condition. In all other cases,

History : The database itself is generated rather, well, generically by scanning a file where I don't know the nature of the content beyond simple node relationships (i.e. I don't know ahead of time all values for "name"). However, I'm thinking that after the flat data storage portion is taken care of I could go in and maybe write some sort of generator for myself that would build up the Ruby classes to deal with the database, and hide the whole thing.

I'm not completely clear on what your trying to accomplish but it sounds like STI may be what your looking for?

Good luck! Tim