Sometimes you have to import two or more xml files in the same way. There are several possibilities: creating a feed configuration for every xml file, creating a PHP function that uses Feed Import API or,
you can take a different approach by using xml xinclude.

Why? Because you'll have to maintain just one feed configuration and you can do this only from UI.
When? Usually when the xml files have the same structure.
How? Pretty simple, using xml XInclude.