how to remove an element if its immediately following an element using xslt

if any placeholder element with attribute x=”test” + text element immediately follow an hg* record that is a duplicate needs to be removed below is the sample xml:

        <block ID="IF5">
        <codes ID="IF5" x="hg5">
            <info>
                <name>ARTICLE</name> 
                <designator>1</designator>
            <info>
        </codes>
        <codes ID="IF5" x="hg5c">
            <info>
                <headtext>PUBLIC</headtext>
            </info>
        </codes>
        <placeholder ID="IF526" x="test">
            <text>SANA</text>
        </placeholder>
        <grade>
            <text>SANA</text>
        </grade>
        <placeholder ID="IF526" x="test">
            <text>SANA</text>
        </placeholder>
    </block>

expected output:

        <block ID="IF5">
        <codes ID="IF5" x="hg5">
            <info>
                <name>ARTICLE</name> 
                <designator>1</designator>
            <info>
        </codes>
        <codes ID="IF5" x="hg5c">
            <info>
                <headtext>PUBLIC</headtext>
            </info>
        </codes>
        <grade>
            <text>SANA</text>
        </grade>
        <placeholder ID="IF526" x="test">
            <text>SANA</text>
        </placeholder>
    </block>

my xslt code look like below:

        <xsl:template match="placeholder[@x='test']" >
        <xsl:choose>
            <xsl:when test="preceding-sibling::*[1][codes[@x='hg*']]">
                <!-- do nothing-->
            </xsl:when>
            <xsl:otherwise>
                <xsl:apply-templates select="@*|node()"/>
            </xsl:otherwise>
        </xsl:choose>
    </xsl:template>