[XSD, XML] Integrating XML attributes onto XML documen

Hello,

I'm trying to integrate a XML main file based on a XSD and a XML (input
file) giving inputs for certain elements of the main file. Does anyone know
some sort of tool, or plugin (for eclipse) that is customizable and is able
to integrate these subjects?

The idea is to build an XML file from a XSD and for certain elements drag
and drop from another XML file and depending on witch I drag or drop it
would change the main XML file.

Example: 
XML main file "cars" with element attributes
XML input file "colors" with elements <type>purple</purple><type>blue</blue>

I would like to drag the color I want to attribute and generate a final
file, for example:
<car><attribute>blue<attribute></car>


Note : This has nothing to do with mapping one XML to another..

Hope I'm not being very confusing.

Pedro