I agree that sometimes there are group issues with domestic students as well. One thing I have found critical in working with students is to tell them why I'm grouping them (e.g. they bring different life experience and knowledge so it builds on what I offer, how it leads to the next task etc.). I believe it is also necessary to include the piece on the value of diversity (rather than assuming this is known) , as the instructor in the video is demonstrating. I have to constantly remind myself that it is not the task that is paramount, it's the learning, so by telling students why, I reinforce my own reasons for the groupings.