master.xml

<events>
    <eventTitle result="error">
        <message>Message Title</message>
        <fieldName1 label="label1" type="missing|invalid" message="Field Message 1" />
        <fieldName2 label="label2" type="missing|invalid" message="Field Message 2" />
    </eventTitle>
</events>

master.xsl

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

<xsl:output method="xml" indent="yes" />

<xsl:template match="events">
	<xsl:apply-templates select="eventTitle" />
</xsl:template>

<xsl:template match="eventTitle">
	<result type="{@result}">
		<title>
			<xsl:value-of select="message" />
		</title>
		<messages>
			<xsl:apply-templates select="*[@message]" />
		</messages>
	</result>
</xsl:template>

<xsl:template match="*[@message]">
	<message>
		<xsl:value-of select="@message" />
	</message>
</xsl:template>

</xsl:stylesheet>