Extend XML Schema enumeration without changing files using it

[iconic944ss]

I've got a lot of XML schemas, let's say a.xsd, b.xsd, c.xsd which contains element types that make use of an enumeration for some of their attributes.So imagine that somewhere in the definition of these types there is:Now I need to add some values to this enumeration, but I cannot touch the enumeration definition as that definition should be kept as it is because it is part of a standard.How can I extend it using another XSD schema WITHOUT changing references in a.xsd, b.xsd and c.xsd?I would like to kind of redefine this Enumeration in a way that everywhere is referenced the new one is used instead of the old one.Thanks in advance!