Is it possible to add one resource dictionary into other one?
Something like:
ResourceDictionary resources = new ResourceDictionary();
resources.Source = new Uri("/MyModule;component/MyModule.xaml",
UriKind.RelativeOrAbsolute);
Application.Current.Resources.MergedDictionaries.Add(resources);
Might be what you're looking for. We use code like this in our Prism Modules.