Discrete Choice Experiment: Two Experiments in One

In this short tutorial, I show you how to combine two DCEs. Hitherto, I had two reasons for this:
1. One of our DCE was too long and we were afraid that participants would not read through all the levels and decide based on the first two lines.
2. One of my students worked with two products, "apples" and "oranges". While attributes of size, form, and price were common, comparing apples to oranges makes no sense. It would make sense to start with apples and make some comparisons, and then go for oranges.
How you can resolve this issue? Here is how ;)