XSLT 2.0 | One Input --> Multiple stylesheets --> Multiple outputs - xslt-2.0

Question

Setup : Saxon HE 9.6 | XSLT 2.0
main.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:import href="first.xsl" />
<xsl:import href="second.xsl" />
<xsl:template match="/">
<xsl:result-document href="output/first.xml" method="xml">
<xsl:apply-imports/> // <-- apply first.xsl
</xsl:result-document>
<xsl:result-document href="output/second.xml" method="xml">
<xsl:apply-imports/> // <-- apply second.xsl
</xsl:result-document>
</xsl:template>
</xsl:stylesheet>
first.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:output indent="yes"/>
<xsl:template match="/">
<feedNumberOne>
<xsl:apply-templates select="products/p[akt = '1' and export='tak']"/>
</feedNumberOne>
</xsl:template>
<xsl:template match="p">
<first>
<product id="{./code}" name="{./front_name}"/>
</first>
</xsl:template>
</xsl:stylesheet>
second.xslt
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:output indent="yes"/>
<xsl:template match="/">
<feedNumberTwo>
<xsl:apply-templates select="products/p[akt = '1' and export='tak']"/>
</feedNumberTwo>
</xsl:template>
<xsl:template match="p">
<second>
<product id="{./code}" name="{./front_name}"/>
</second>
</xsl:template>
</xsl:stylesheet>
Q : How to have 1 input, many xslt stylesheets imported with many xml output files in a single transformation
input :
<?xml version="1.0" encoding="UTF-8"?>
<products>
<p>
<code>1030037</code>
<front_name>Zelmer</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1030811</code>
<front_name>Sony</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>900142</code>
<front_name>Severin</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1030144</code>
<front_name>Ubisoft</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1029390</code>
<front_name>Blanco</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1029750</code>
<front_name>Franke</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1028728</code>
<front_name>WD</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1030916</code>
<front_name>Electrolux</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031097</code>
<front_name>High Sierra</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1030125</code>
<front_name>Magnat</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031195</code>
<front_name>Curver</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1031061</code>
<front_name>High Sierra</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1029787</code>
<front_name>Franke</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031450</code>
<front_name>Spokey</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1029699</code>
<front_name>Franke</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1029130</code>
<front_name>Samsung</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1028754</code>
<front_name>Technaxx</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1028822</code>
<front_name>Netgear</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1030923</code>
<front_name>Electrolux</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1031318</code>
<front_name>Black&Decker</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031625</code>
<front_name>Russell Hobbs</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1031664</code>
<front_name>HMS</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031627</code>
<front_name>Russell Hobbs</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1031680</code>
<front_name>Nikwax</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031899</code>
<front_name>Wiko Mobile</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031758</code>
<front_name>DeLonghi</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1032377</code>
<front_name>MSI</front_name>
<export>nie</export>
<akt>0</akt>
</p>
<p>
<code>1031779</code>
<front_name>DeLonghi</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032865</code>
<front_name>Samsung</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1031848</code>
<front_name>American Tourister</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032617</code>
<front_name>AMD</front_name>
<export>nie</export>
<akt>1</akt>
</p>
<p>
<code>1031923</code>
<front_name>Dyson</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1032998</code>
<front_name>Pioneer</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032002</code>
<front_name>Vivanco</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1032104</code>
<front_name>Sony</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032358</code>
<front_name>Adidas</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032741</code>
<front_name>Samsonite</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1032928</code>
<front_name>SanDisk</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1030230</code>
<front_name>Printe</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032287</code>
<front_name>Netis</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1031984</code>
<front_name>Krusell</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1029857</code>
<front_name>Franke</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1030681</code>
<front_name>Printe</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1032886</code>
<front_name>Alcatel</front_name>
<export>tak</export>
<akt>1</akt>
</p>
<p>
<code>1032688</code>
<front_name>HP</front_name>
<export>tak</export>
<akt>0</akt>
</p>
<p>
<code>1028743</code>
<front_name>Acer</front_name>
<export>tak</export>
<akt>0</akt>
</p>
</products>

Answer 1

As #MartinHonnen says, the classic solution is to use modes.
XSLT 3.0 introduces the default-mode attribute on xsl:stylesheet which makes this a bit easier.
EDIT #Piotr Dajlido - SOLUTION BELOW
Note the usage of mode attribute in the first.xsl
main.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs">
<xsl:import href="first.xsl" />
<xsl:import href="second.xsl" />
<xsl:output indent="yes"/>
<xsl:template match="/">
<xsl:result-document href="output/first.xml" method="xml">
<xsl:call-template name="first">
</xsl:call-template>
</xsl:result-document>
<xsl:result-document href="output/second.xml" method="xml">
<xsl:call-template name="second"/>
</xsl:result-document>
</xsl:template>
</xsl:stylesheet>
first.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs"
version="2.0">
<xsl:output indent="yes"/>
<xsl:template match="/" name="first">
<feedNumberOne>
<xsl:apply-templates select="products/p[akt = '1' and export='tak']" mode="first"/>
</feedNumberOne>
</xsl:template>
<xsl:template match="p" mode="first">
<first>
<product id="{./code}" name="{./front_name}"/>
</first>
</xsl:template>
</xsl:stylesheet>