call template when values match. part2

i have the following xml input

<RS>
      <SAvailRQ>
            <Code>AL</Code>
            <FNum>131</FNum>
      </SAvailRQ>
<SMapRS>
  <SMapResponses>
      <SMapResponse>
            <SegInfo FNum="131">
                  <Departure LocationCode="MIA"/>
                  <Arrival LocationCode="LAX"/>
                  <Marketing Code="AL"/>
            </SegInfo>
            <SMapDetails>
            <CabClass CabinType="Economy" Name="AC DF">
                  <ARows>
                        <ARow RowNumber="12">
                              <ASeats>
                                    <ASeat Availability="A" Characteristics="W|K|F|PS" Number="A"/>
                              </ASeats>
                              <ARowCharacteristics CharacteristicList=""/>
                        </ARow>
                  </ARows>
                  </CabClass>
            </SMapDetails>
      </SMapResponse>
      <SMapResponse>
            <SegInfo FNum="118">
                  <Departure LocationCode="LAX"/>
                  <Arrival LocationCode="MIA"/>
                  <Marketing Code="AL"/>
            </SegInfo>      
            <SMapDetails>
                  <CabClass CabinType="Economy" Name="AC DF">
                        <ARows>
                              <ARow RowNumber="12">
                                    <ASeats>
                                          <ASeat Availability="A" Characteristics="W|K|F|PS" Number="A"/>
                                    </ASeats>
                                    <ARowCharacteristics CharacteristicList=""/>
                              </ARow>
                        </ARows>
                  </CabClass>
            </SMapDetails>
      </SMapResponse>      
   </SMapResponses>
</SMapRS>      
</RS>      


#1.
I need logic that will execute the follwing template
  <xsl:apply-templates select="SMapResponses/SMapResponse/SMapDetails/CabClass" mode="SDisplay"/>
 
if RS/SAvailRQ/FNum matches that found in RS/SMapRS/SMapResponses/SMapResponse/SegInfo/@FNum

per another question asked i have the following partial solution:
<xsl:variable name="this-fnum" select="ancestor::RS/SAvailRQ/FNum"/>
<xsl:apply-templates select="SMapResponses/SMapResponse/SegInfo[@FNum = $this-fnum]"/>

and this worked successfully but how do i apply this same concept new template call using SMapDetails grouped within SMapResponse?


#2.
similarly, i have for-each statement where again I need to have executed only when Fnum is found within xml


        <xsl:for-each select="SMapResponses/SMapResponse">                  //here only do this when Fnum is equal
            <xsl:variable name="pos" select="position()"/>
            <xsl:for-each select="SMapDetails/CabClass/ARows/ARow">
                        ....
            </xsl:for-each>
        </xsl:for-each>