var catalog = new DirectoryCatalog(@".\");
var rootCatalog = new FilteredCatalog(catalog, cpd=>!cpd.Metadata.ContainsKey("Scope") || (cpd.Metadata.ContainsKey("Scope") && cpd.Metadata["Scope"].Equals("Root"));
var childCatalog = new FilteredCatalog(catalog, cpd=>cpd.Metadata.ContainsKey("Scope") && cpd.Metadata["Scope"].Equals("Child"));
var rootContainer = new CompositionContainer(rootCatalog);
var childContainer = new CompositionContainer(childCatalog, rootContainer);