I would like to group based on fields of row element (combination of StackNumber,BlockNumber and LocationCode) and select only higher BookVersion (BookVersion) based rows in particular group(combination of StackNumber,BlockNumber and LocationCode) and also to select the rows of DeliveryMode with the value as TRANSIT.

Here is the input document

<?xml version="1.0"?>
<Output>
    <row>
        <StackNumber>19</StackNumber>
        <BlockNumber>61001</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>03</BookVersion>
        <StoreNumber>1010</StoreNumber>

    </row>
    <row>
        <StackNumber>20</StackNumber>
        <BlockNumber>61001</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>01</BookVersion>
        <StoreNumber>1011</StoreNumber>
    </row>
    <row>
        <StackNumber>20</StackNumber>
        <BlockNumber>61001</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>02</BookVersion>
        <StoreNumber>1013</StoreNumber>
    </row>
    <row>
        <StackNumber>21</StackNumber>
        <BlockNumber>61001</BlockNumber>
        <DeliveryMode>RECVD</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>03</BookVersion>
        <StoreNumber>1022</StoreNumber>
    </row>
    <row>
        <StackNumber>21</StackNumber>
        <BlockNumber>61001</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>03</BookVersion>
        <StoreNumber>1022</StoreNumber>
    </row>
    <row>
        <StackNumber>22</StackNumber>
        <BlockNumber>15098</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>01</BookVersion>
        <StoreNumber>1010</StoreNumber>
    </row>
    <row>
        <StackNumber>22</StackNumber>
        <BlockNumber>22456</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>02</BookVersion>
        <StoreNumber>1011</StoreNumber>
    </row>
    <row>
        <StackNumber>22</StackNumber>
        <BlockNumber>22456</BlockNumber>
        <DeliveryMode>TRANSIT</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>03</BookVersion>
        <StoreNumber>1012</StoreNumber>
    </row>
    <row>
        <StackNumber>22</StackNumber>
        <BlockNumber>22456</BlockNumber>
        <DeliveryMode>RECVD</DeliveryMode>
        <LocationCode>MON</LocationCode>
        <BookVersion>02</BookVersion>
        <StoreNumber>1021</StoreNumber>
    </row>
</Output>
XSL (using saxon 9 parser) that I wrote:

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

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

    <xsl:key name="transitGroup" match="row" use="concat(StackNumber,BlockNumber,LocationCode)"/>

    <xsl:template match="/">
        <Output>
            <xsl:for-each select="//row[generate-id(.) = generate-id(key('transitGroup',concat(StackNumber,BlockNumber,LocationCode))[1])]">
                <xsl:variable name="BookVersion" select="key('transitGroup',concat(StackNumber,BlockNumber,LocationCode))/BookVersion"/>
                <xsl:if test="DeliveryMode = 'TRANSIT'">
                    <row>
                        <StackNumber>
                            <xsl:value-of select="StackNumber"/>
                        </StackNumber>
                        <BlockNumber>
                            <xsl:value-of select="BlockNumber"/>
                        </BlockNumber>
                        <LocationCode>
                            <xsl:value-of select="LocationCode"/>
                        </LocationCode>
                        <StoreNumber>
                            <xsl:value-of select="StoreNumber"/>
                        </StoreNumber>

                        <xsl:for-each select="$BookVersion">

                            <xsl:sort select="." data-type="number" order="descending"/>

                            <xsl:if test="position()=1">
                                <BookVersion>
                                    <xsl:value-of select="."/>
                                </BookVersion>
                            </xsl:if>
                        </xsl:for-each>
                    </row>
                </xsl:if>
            </xsl:for-each>
        </Output>
    </xsl:template>
</xsl:stylesheet>


I wrote  this above one but can't figure out to select correct store number based on greater value based element 'BookVersion' in each group.

example group must be printed like this .

<row>
<StackNumber>20</StackNumber>
<BlockNumber>61001</BlockNumber>
<LocationCode>MON</LocationCode>
<StoreNumber>1013</StoreNumber>
<BookVersion>02</BookVersion>
</row>

I'm getting wrong store number here for a particular selected group. I'm struck to proceed further here, I will appreciate if some body can lead me the way to write correct it in this XSL.