Cursor Selection

I have rendered a grid of cubes on screen and would like to know the best approach for selecting one with the cursor. I have looked at the SDK example and i am fine up to the stage where it gets the cursor position and works out the ray vector. I''m generally unsure about the principle behind the ray interacting with the triangles in the cube. Since the SDK example only deals with individual triangle as being shown selected, i''m unsure about how i would recognise the intersected triangle as part of which ever cube it is a part of. The general concept of the App is to select a cube from a grid of cubes. Can anyone help me please? regards, ace