Dinesh Asanka reminds me not to use the designer for tough Azure ML problems:
Let us see how we can extend the standard classification to Ensemble Classifiers in Azure Machine Learning. Before we discuss the details of this configuration, you can view or download the experiment from Ensemble Classification
The following figure shows the complex layout of the Ensemble Classifiers in Azure Machine Learning.
Dinesh is not kidding about that complexity. This is definitely a use case for the Azure ML SDK.