Combining two different fact "grains"

I'm trying to get one cube to display two different grains of data:

1) Vehicle measures - such as total time and total miles.

2) Trip measures - such as total trip time and total trip miles.

How would I accomplish this? I assume that the measures have to be in the same fact table?

Thanks for your time!

I found one way of doing it:
I created both a vehicle and a trip cube. I then created a virtual cube that references both of these cubes.

Is there another approach that I could take?