installatend_a_pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  
  <parent>
    <groupId>installatend</groupId>
    <artifactId>parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <relativePath>../parent</relativePath>
  </parent>

  <groupId>installatend</groupId>
  <artifactId>a</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>A</name>
</project>

installatend_b_pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  
  <parent>
    <groupId>installatend</groupId>
    <artifactId>parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <relativePath>../parent</relativePath>
  </parent>

  <groupId>installatend</groupId>
  <artifactId>b</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>B</name>
</project>

installatend_parent_pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>installatend</groupId>
  <artifactId>parent</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>Parent</name>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.1</version>
          <configuration>
            <installAtEnd>true</installAtEnd>
          </configuration>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

installatend_pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>installatend</groupId>
  <artifactId>aggregator</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>aggregator</name>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  
  <modules>
    <module>parent</module>
    <module>a</module>
    <module>b</module>
  </modules>
</project>