Hi! Yes, you can substitute; when it's a 'small' ingredient, it doesn't matter. The thing is, cider vinegar has flavor, whereas the white vinegar doesn't (white vinegar just adds acidity). So the flavor will be a bit different. In barbecue beef, I don't think you'd even notice the difference, with all the other flavors.
You have to be a bit more careful substituting cider for white, though--in a sweet recipe, I don't think it would taste good.