Parent, child and sibling relationships - Is this possible?

[harvey]

OK, here's the scenario: I've been asked to develop a new site for Ford Motor Co. (yeah riiiiight!).

I have a definition of 'Car' (Fiesta, Focus, Mondeo etc.).

'Car' is a parent definition of 'Model' (1.2 Popular, 2.0 Sport etc.).

'Model' is a parent definition of 'Colour'. I have populated 'Colour' with Red, Blue, Green, Yellow, Black, White & Silver.

Now I want to display a content page for each 'Model' which will include the colours available. However, a 1.2 Popular is only available in Red, Blue and Yellow, a 2.0 Sport in Red, Blue, Black and Silver etc.

Have I set up my relationships correctly, and if so how do I specify within the content entry for a 'Model' which colours are available, and how would I then display them on a content page?

Is this even possible?