How to execute a maven plugin twice with different property

Given the simple Maven Source Plugin configuration (as an example) you have a shared configuration across all of its executions (outside the executions element) and then a custom configuration per each execution, for the same phase, as requested by your question:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-source-plugin</artifactId>
            <version>2.4</version>
            <configuration>
                <includePom>true</includePom>
            </configuration>
            <executions>
                <execution>
                    <id>test-id1</id>
                    <phase>verify</phase>
                    <goals>
                        <goal>jar</goal>
                    </goals>
                    <configuration>
                        <finalName>aaa</finalName>
                    </configuration>
                </execution>
                <execution>
                    <id>test-id2</id>
                    <phase>verify</phase>
                    <goals>
                        <goal>jar</goal>
                    </goals>
                    <configuration>
                        <finalName>bbb</finalName>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

The configuration entry <includePom>true</includePom> will in this case be merged with the custom configurations of each execution and as such centralize the common configuration as plugin generic configuration.

For more details on the different level of configurations, you can check official Maven documentation, here, in particular the example “Configuring compile to run twice”. Further details are also available on the official POM documentation, here, Plugins section.