I don't think ordering 4 or 5 items together would increase chances of customs interference. I've ordered several items together, the only items that seem to be checked by customs are the ones in larger packages. But sometimes even the larger packages get through without checking. All my small packages get through without opening and checking by customs.
But once customs gets hold of the package, expect the package to be delayed by weeks. I have a package that's been sitting in customs for more than 20 days. It was stopped for customs check on 27 Sep and on 20th Oct they put some duty on it.