<plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>step-exec2-api</id>
                        <phase>process-classes</phase>
                        <goals>
                            <goal>exec</goal>
                        </goals>
                        <configuration>
                            <executable>bundle</executable>
                            <workingDirectory>target/slate-api</workingDirectory>
                            <arguments>
                                <argument>install</argument>
                            </arguments>
                        </configuration>
                    </execution>
                    <execution>
                        <id>step-exec3-api</id>
                        <phase>process-classes</phase>
                        <goals>
                            <goal>exec</goal>
                        </goals>
                        <configuration>
                            <executable>bundle</executable>
                            <workingDirectory>target/slate-api</workingDirectory>
                            <arguments>
                                <argument>exec</argument>
                                <argument>middleman</argument>
                                <argument>build</argument>
                            </arguments>
                        </configuration>
                    </execution>
                </executions>
            </plugin>