Chained Mapping
Altova website: 
Chained Mapping Video Tutorial
This tutorial shows how to work with multiple target components. The goal of the tutorial is to merge data from two source files into one target file, then filter the data of this target file, and pass the filtered data to the second target file. The image below illustrates an abstract model of the data transformation described in this tutorial.
In the diagram above, the data is first merged from two source files (Books.xml and Library.xml) into one target file called MergedLibrary.xml. Then the data is transformed with a filtering function and passed further to the next component called FilteredLibrary.xml. Note that FilteredLibrary.xml is based on the Library.xsd schema. The intermediate component acts both as a data target and source. In MapForce, this technique is known as a chained mapping. Chained mappings allow previewing and saving the intermediate result(s) of the mapping (in our case, MergedLibrary.xml) and the result of the last target component (in our case, FilteredLibrary.xml).
To carry out the transformation, take the steps described in the subsections below.
For another example of a chained mapping, see the video tutorial linked at the top of the page.