XSLT - Remove output parent element if no child element was mapped - xslt-1.0

Question

Imagine the following schema as input
<xs:schema>
<xs:element name="In">
<xs:complexType>
<xs:sequence>
<xs:element name="InA">
<xs:complexType>
<xs:sequence>
<xs:element name="InA1" type="xs:string" />
<xs:element name="InA2" type="xs:string" />
<xs:element name="InA3" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="InB">
<xs:complexType>
<xs:sequence>
<xs:element name="InB1" type="xs:string" />
<xs:element name="InB2" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
And example would be
<In>
<InA>
<InA1>InA1_0</InA1>
<InA2>InA2_0</InA2>
<InA3>InA3_0</InA3>
</InA>
<InB>
<InB1>InB1_0</InB1>
<InB2>InB2_0</InB2>
</InB>
</In>
Now, i need to map this to another schema, as some of the rules are:
Out/Out1 mapped from In/InA/InA1 if value != ''
Out/Out2 mapped from In/InB/InB2 if value != ''
Out/Out3 mapped from In/InA/InA3 if value != ''
Out should only be present if at least one of the childs was mapped
The only way I figured to do this would be to do an if before Out element, but this is very tedious and problematic the more childs Out has.
<xsl:if test="/In/InA/InA1 != '' and /In/InA/InB2 != '' and /In/InA/InA3 != ''">
<Out>
<xsl:if test="/In/InA/InA1 != ''">
<Out1>
<xsl:value-of select="/In/InA/InA1/text()">
</Out1>
</xsl:if>
<xsl:if test="/In/InA/InB2 != ''">
<Out2>
<xsl:value-of select="/In/InB/InB2/text()">
</Out2>
</xsl:if>
<xsl:if test="/In/InA/InA3 != ''">
<Out3>
<xsl:value-of select="/In/InA/InA3/text()">
</Out3>
</xsl:if>
</Out>
</xsl:if>
Anyone has any other way of doing this in a single map?

Answer 1

here is what I came out with. The idea is to do the inner map in a variable and then check if the variable is empty. If it is not, then i can map.
<xsl:variable name="out-Node">
<xsl:if test="/In/InA/InA1 != ''">
<Out1>
<xsl:value-of select="/In/InA/InA1/text()">
</Out1>
</xsl:if>
<xsl:if test="/In/InA/InB2 != ''">
<Out2>
<xsl:value-of select="/In/InB/InB2/text()">
</Out2>
</xsl:if>
<xsl:if test="/In/InA/InA3 != ''">
<Out3>
<xsl:value-of select="/In/InA/InA3/text()">
</Out3>
</xsl:if>
</xsl:variable>
<xsl:if test="$out-Node != ''">
<Out>
<xsl:copy-of select="$out-Node"/>
</Out>
</xsl:if>
Of course, this approach must have it issues, I guess one of them would be performance.