XSLT - Merge two element nodes with different local names

Question

I would like to use XSLT to merge two element nodes where their local names are different.

e.g. Merge file1.xml

<A>
    <B>
        <C>
            <D>Value</D>
        </C>
    </B>
    <G>
        <C>
            <H>Value</H>
        </C>
    </G>
</A>

with file2.xml

<A>
    <E>
        <C>
            <F>Value</F>
        </C>
    </E>
</A>

to get output file3.xml

<A>
    <B>
        <C>
            <D>Value</D>
            <F>Value</F>
        </C>
    </B>
    <G>
         <C>
            <H>Value</H>
            <F>Value</F>
        </C>
    </G>
</A>

I basically want to treat E as a wildcard. Is this possible? If so, could you provide some XSLT that would work for this? I've been trying for a number of hours and can't seem to come up with a solution.

EDIT: asked for attempts... This XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output indent="yes"/>
<xsl:template match="@*|node()">
    <xsl:copy>
        <xsl:apply-templates select="@*|node()" />
    </xsl:copy>
</xsl:template>
<xsl:template match="A">
    <xsl:copy>
        <xsl:apply-templates select="*"/>
        <xsl:apply-templates select="document('file1.xml')/A/node()" />
    </xsl:copy>
</xsl:template>
<xsl:template match="C">
    <xsl:copy>
        <xsl:apply-templates select="*"/>
        <xsl:apply-templates select="document('file1.xml')/A/./C/*" />
    </xsl:copy>
</xsl:template>
</xsl:stylesheet>

Gave this output:

<?xml version="1.0"?>
<A><E>
    <C><F>Value</F></C>
</E>
<B>
    <C><D>Value</D></C>
</B>
<G>
    <C><H>Value</H></C>
</G>
</A>