Grouping of similer nodes - xslt-2.0

Question

I have follwing problem in grouping the similer nodes with xsl:
input:
<?xml version="1.0" encoding="UTF-8"?>
<concept id="ads">
<p>para1 content goes here</p>
<Bullet>1</Bullet>
<Bullet>2</Bullet>
<Bullet>3</Bullet>
<p>para2 content goes here</p>
<Bullet>4</Bullet>
<Bullet>5</Bullet>
<p>para2 content goes here</p>
</concept>
Output should be:
<?xml version="1.0" encoding="UTF-8"?>
<concept id="ads">
<p>para1 content goes here</p>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
<p>para2 content goes here</p>
<ul>
<li>4</li>
<li>5</li>
</ul>
<p>para2 content goes here</p>
</concept>
All the "Bullet" element which does not have imideate preceding sibling as "Bullet" should wrap up in "UL" and "Li" elements.
I am trying something like this but not able to achive the result:
<xsl:for-each select="Bullet[not(preceding-sibling::Bullet)]">
<ul>
<xsl:copy-of select="."/>
<xsl:variable name="current-name" select="generate-id(.)"/>
<xsl:for-each select="following-sibling::*[Bullet][generate-id(preceding-sibling::*[Bullet]) = $current-name]">
<xsl:copy-of select="."/>
</xsl:for-each>
</ul>
</xsl:for-each>
Please help.
---Related Question ----
This works fine on given xml input, but
1. In my actual xml these <Bullet> tags can appear anywhere under concept node, so grouping with <p> element does not work in that case.
Currently I am processing all the nodes except "Bullet" nodes, so i need to match only <Bullet> nodes which is having immediate following sibling as <Bullet> and wrap the sequence in <ul> and each <Bullet> in <li>. My current context node is <concept>.
Current stylesheet as follows:
nodes which should render at the same place as in input.-->
Actual XML pattern:
<?xml version="1.0" encoding="UTF-8"?>
<concept id="ads">
<p>para1 content goes here</p>
<Body-text>Body1 content goes here</Body-text>
<Bullet>1</Bullet>
<Bullet>2</Bullet>
<Bullet>3</Bullet>
<Body-text>Body2 content goes here</Body-text>
<p>para2 content goes here</p>
<Bullet>4</Bullet>
<Bullet>5</Bullet>
<p>para3 content goes here</p>
<Bullet>6</Bullet>
<Bullet>7</Bullet>
<Body-text>Body2 content goes here</Body-text>
<Bullet>6</Bullet>
<Bullet>7</Bullet>
</concept>
<concept id="ads">
<p>para1 content goes here</p>
<Body-text>Body1 content goes here</Body-text>
<Bullet>1</Bullet>
<Bullet>2</Bullet>
<Bullet>3</Bullet>
<Body-text>Body2 content goes here</Body-text>
<p>para2 content goes here</p>
<Bullet>4</Bullet>
<Bullet>5</Bullet>
<p>para3 content goes here</p>
<Bullet>6</Bullet>
<Bullet>7</Bullet>
<Body-text>Body2 content goes here</Body-text>
<Bullet>6</Bullet>
<Bullet>7</Bullet>
</concept>

Answer 1

This stylesheet:
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()[1]|#*"/>
</xsl:copy>
<xsl:apply-templates select="following-sibling::node()[1]"/>
</xsl:template>
<xsl:template match="Bullet[preceding-sibling::node()[1]
[not(self::Bullet)]]">
<ul>
<xsl:call-template name="makeLi"/>
</ul>
<xsl:apply-templates select="following-sibling::node()
[not(self::Bullet)][1]"/>
</xsl:template>
<xsl:template match="Bullet" name="makeLi">
<li>
<xsl:value-of select="."/>
</li>
<xsl:apply-templates select="following-sibling::node()[1]
[self::Bullet]"/>
</xsl:template>
</xsl:stylesheet>
EDIT: Just changing the following applying "first Bullet" rule to first next not Bullet instead of p.
Output (wrapping your input with root element to be wellformed):
<concept id="ads">
<p>para1 content goes here</p>
<Body-text>Body1 content goes here</Body-text>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
<Body-text>Body2 content goes here</Body-text>
<p>para2 content goes here</p>
<ul>
<li>4</li>
<li>5</li>
</ul>
<p>para3 content goes here</p>
<ul>
<li>6</li>
<li>7</li>
</ul>
<Body-text>Body2 content goes here</Body-text>
<ul>
<li>6</li>
<li>7</li>
</ul>
</concept>
<concept id="ads">
<p>para1 content goes here</p>
<Body-text>Body1 content goes here</Body-text>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
<Body-text>Body2 content goes here</Body-text>
<p>para2 content goes here</p>
<ul>
<li>4</li>
<li>5</li>
</ul>
<p>para3 content goes here</p>
<ul>
<li>6</li>
<li>7</li>
</ul>
<Body-text>Body2 content goes here</Body-text>
<ul>
<li>6</li>
<li>7</li>
</ul>
</concept>
Note: Fine grained traversal.
With grouping, this stylesheet:
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="concept">
<xsl:copy>
<xsl:copy-of select="#*"/>
<xsl:for-each-group select="*"
group-adjacent="boolean(self::Bullet)">
<xsl:choose>
<xsl:when test="current-grouping-key()">
<ul>
<xsl:apply-templates select="current-group()"/>
</ul>
</xsl:when>
<xsl:otherwise>
<xsl:apply-templates select="current-group()"/>
</xsl:otherwise>
</xsl:choose>
</xsl:for-each-group>
</xsl:copy>
</xsl:template>
<xsl:template match="Bullet">
<li>
<xsl:value-of select="."/>
</li>
</xsl:template>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
EDIT: Ussing group-adjacent.

Answer 2

This XSLT 2.0 transformation:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="/*">
<xsl:copy>
<xsl:copy-of select="#*"/>
<xsl:for-each-group select="*" group-starting-with="p">
<xsl:copy-of select="current-group()[1]"/>
<xsl:if test="current-group()[2]">
<ul>
<xsl:apply-templates select="current-group()[position() gt 1]"/>
</ul>
</xsl:if>
</xsl:for-each-group>
</xsl:copy>
</xsl:template>
<xsl:template match="Bullet">
<li><xsl:value-of select="."/></li>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<concept id="ads">
<p>para1 content goes here</p>
<Bullet>1</Bullet>
<Bullet>2</Bullet>
<Bullet>3</Bullet>
<p>para2 content goes here</p>
<Bullet>4</Bullet>
<Bullet>5</Bullet>
<p>para2 content goes here</p>
</concept>
produces the wanted, correct result:
<concept id="ads">
<p>para1 content goes here</p>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
</ul>
<p>para2 content goes here</p>
<ul>
<li>4</li>
<li>5</li>
</ul>
<p>para2 content goes here</p>
</concept>
Do note: The use of <xsl:for-each-group> with the group-starting-with attribute and the current-group() function.